All you need is good intentions and to be relaxed enough to live up to them.
The problem of course: Relaxation is rarest in the moments you described. I see two ways things can still work out:
- You start being calmer in smaller situations, like in traffic and little by little it will also help you with bigger situations. How exactly you stay calm is probably something personal. I need to rationalize and take a moment to think (simply not acting on anything until I have thought it through as a precaution). Further I can remind myself of how little this moment matters in the big picture. Especially at work: it's just a game we play to earn money, it's not my life.
- You can try to reduce stress in general. There are many ways to do this: No driving, no group work, less work, more generosity towards yourself (especially embracing laziness), having a plan for a better future, taking a breath of fresh air (join the smokers, just don't get started smoking :) ), avoiding toxic power hierarchies, shedding responsibilities (especially professionally: make clear where your responsibility ends and worry less about the rest; where you are responsible also claim some authority)
About fakes: I personally hate anything fake, but this is especially true for two-faced fakers that kind of lie by doing it. If you are acting to be the person you want to be it is different: It has the underlying truth that you want to be like this. It can quickly begin to feel natural to act that way and become much less fake and more relaxing. Just make sure that it feels like an accomplishment if you act like you want to act (and not like you have to swallow anger and frustration and risking to burst at some point).