Result - Angermanagement

When do you lose temper? Did it start recently? Also: What is your age, if you are between 13 and 20, it is likely a hormonal thing and you should try to learn to count.

Losing temper can come from hormonal inbalance, stress, justified irritation (though irritation itself can have many different causes), too little sleep, but also neurological/cognitive dissonance caused by many different factors (from light/sound sources, to actual conflicting information).

In case you are under a large amount of work stress, of course this can cause 'a short fuse'. Your mind can not cope with the given signals and you respond with the irritation about other stressfactors, that is not connected with the situation at hand. Because it is an emotional reflex, it is difficult to do something about it at the moment. I suggest that after having had a stressful time/moment/period, you take a moment away from everyone and everything and blow off steam. This can be by 'silence', 'meditation', a punchbag, running or listening to music (preferably classical or ambient).

In other cases, I would suggest you consult a professional.

With hormonal inbalances, it might be due to gland over/under production of enzyms and hormones, but it can just as well be a insuline/glucose issue (meaning early diabetes).

Sometimes you really just are in 'the wrong crowd', people around you behave against your most basic values: Being on time/late, using foul language or not, respecting others or not, etc. This can cause a continuous build up of internal strife, which will (if continuously) result in fast bursts of reactions from you. This is basically a form of neural/cognitive dissonance.

In case you are not in any of the above, there can still be many different causes. One of the most 'devious' ones, is cognitive dissonance. Why? Because mostly people don't recognize it. Heck, even professionals often miss signals. What does it mean? Your brain is basically a network of neural paths, which allows electrical currents of different strengths to influence parts of the brain depending on combinations and strength. We are born with a blueprint given by our parents, but are building our own actual network from the moment the brain is started up in the womb. What this means is the neural network will be 'etched' according to the decision tree you build from everything you learn. If something fits the patterns you create nicely, it causes a 'ressonance', like when listening to sad music, you feel sad, and doing something where someone reacts happy can cause your nervous system to cause 'happy hormones' to be emitted into your bloodstream. Dissonance is the oposite and causes your brain and nervous system irritation. Sounds, ideas, feelings, sights can all cause ressonance or dissonance. 

In any of the the above cases, I suggest you do one thing first (you already started with this question): Write it down. 
I use the method I created, called: 'Affairs of the state'. This means you write down the subject you are unaware of why you act in such way and then start to go by 5 basic sections that go for everything. The first is: What happens right before you get angry. Then you see what other elements you can find in your life that are connected to the same feelings. Historically.

Evolution of the brain - Short Thought 3

Do we have free will or are our actions controlled by our subconscious?

Yes.
With this answer to your dual question, you mind will question which I answer. Thus you didn't 'automatically' responded to it.

First off: 'free will', is a religious infused concept. 
Consciousness is the part that makes us human. The ability to plan and reflect. Other primates lack this consciousness.

What we call subconsciousness is basically our basic neural adaptability system, which creates decision trees or 'instinctive behavior'. What animals show as behavior from instinct is what humans see in themselves as subconscious.

The first time we encounter a situation, we will evaluate, cognitively what the risks, chances, probabilities there are. When we have planned and executed actions, they become a blueprint for the next time you encounter the same kind of situation. Still, humans also have gained the possibility to have abstract thoughts and concepts, these are not behavioral. This results in the answer: we are conscious, which gives us to choose. We also are primarily a result of millions of years of evolution, which causes us to learn, adapt and behave much in the same way as other animals: instinctive.

The parts that have been 'etched', we don't think about it anymore. They are an 'agreement' between events and your neural system, to respond in a previous acted way. If the event happens more often, the response will become automatic and will not be a 'choice' anymore. 

Concluded: yes, we have free will over what we are conscious about, and are controlled by our subconscious over what we don't (anymore).

Evolution of the brain - Short Thought 2

Deja vu (as far as I have been able to investigate and incorporate existing research) is the moment the mind recognizes a pattern that has been (at some prior time) 'considered'. This means that the brain has a response structure for it and at the moment of deja vu, it fills in the blanks. That is why the consciousness feels everything that transpires is predicted. But this only goes for the very basic response to stimulus. 

We as humans are evolved from a long line of organisms that were (for a long time) not the top of the food chain. Our brains is the evolved version of the brain of other primates. However, our line has had the luxury to gain so much overhead in responses, that we could counter possible threats, before they occurred. This means that our system has space and basal response blueprints (instincts) embedded that are not used anymore. These options made us, as species become self aware. The same options caused us to become 'religious' (seeking a parent outside, or generally called animism), plan extensive, become verbal in more complex ways and sometimes have Hotwired in the complex structure of neurons. Our brain is behaving primarily to respond to threats. As we don't have those in all levels of society anymore, there are levels where most of these parts of the brain are used for more cognitive options. However, the structures in which the brain is wired is inherited to extend. The decisions are caused by impulses coming in initially. As we come to a moment of deja vu, some arbitrary part of such a decision tree, is activated and the brain shoots hormones and other neurotoxins into the bloodstream to activate defenses of the organism. Such gives the organism a hastened response (heightened awareness) and the moment the brain sees something, the organism has the idea it has already transpired. We as humans are aware of direction of time and know that we can't act what has already transpired, so our consciousness tries to make the event fit and you get the 'idea' that it was a repetition of an earlier event (but as we KNOW we haven't been in that specific situation, we tell ourselves it must have been a dream).

In base a 'deja vu', is nothing more than a wireframe that falls out of the cupboard, and you remember what it would have looked like if you had finished it.

Evolution of the Brain - a short thought 1

The brain is evolved from millions of years of neural synapses integrating (as said by others much like the processors we create for computers etc), when life was but worms, there were still only a few strands of nerves. A small lump in the 'seat'. What was the 'brain' set to? For food. The worm is one long intestine and basically we are a intestine with vertibrates. Our brain has been evolving ever since life became multiple celltypes with specific functions. When complex animals arose, the brain was already a complex neural box. It was so intrinsic that even mice have basically selfawareness options (who says they aren't?). But the brain still has the same function over all those millions of years: Making sure the body gains food and survives dangers in doing so. We as mammals have been on lower steps of the food chain for thousands of thousands of years. (imagine that. A life span of about 40 years and so generations every 15 to 20 years....imagine how many ancestral generations have gone before THAT point.). Then the weather changed, climate changed and we got less predators to take care of, but we still needed to find food. We ate what was in trees, bushes, die with failure, live with good food. Those choices are all embedded in the blueprint of our brain. They are the unlearned reflexes. Many of them come to pass each generation, without being triggered. And from that moment on, the brain needs less for certain type of reflexes. Eventually we are in our current era and we are the top of the food chain and we changed the ability of running from danger, to preparing for danger for many hundreds of thousands of years. Now, we don't have to run anymore, but some of the reflexes don't die that easily (hence religion and other fear aspects, causing diversion and anger).
We are in a time where the brain evolves on. It might become smaller, but not 'lighter' per se. The density changes, but also its functions 'narrow'. Who of us still know from instinct what to do with babies? With a wild animal attacking us? With how the weather predicts the effects on crops tomorrow? We are all losing parts that are 'irrelevant' to the specific 'bloodline'. Those in cities don't know about carpenting or farming, while in the suburb there will be those that still know. Life still requires it from them to sometimes build something themselves. The same happens for many things, not just 'job' related, but also personal. In the country, people are welcoming to new (new blood, information, etc), but also cautious of differences (dangerous behavior, different unknown bloodlines and physical attributes). In the suburbs where all come together, it is a mediate, while in the city it is the same as in the country, but reversed. They are less welcoming (busy lives, close quarters and thus more shortlived interhuman contacts), but also less cautious. In all, the brain grows smaller, but not around the globe. There are likely locations where it grows. 

It will also still depend on the activities within the bloodlines, whether there is either higher density or loss of reflex/cognitive abilities.