How do you personally keep your emotions in check?

Bear with me as my description for this may not be well written it is late in rainy england after all

What I mean by this is during a conversation with my flatmate the other day I made the statement that he isn’t vert outwardly emotional. He took this to mean that I was calling him unemotional, but I was making an observation about how he expresses himself.
His general persona tends to be quite even but then every so often he will have manic outbursts of aggression not harmfully or sadness that appear to make little sense. I have noticed this amongst a few of my male friends. In particlar an ex who was generally a happy person who claimed to be unaffected by other peoples opinions of him and such and yet every year like clockwork he will have two weeks where he becomes severely depressed but will suddenly snap out of it.

What I am wondering is; is this typical of men? Is it merely a coping mechanism for different personalities?

I myself am very outwardly emotional for both highs and lows…how is it you keep your personality going on a day-to-day basis?