My boyfriend should know this

Because sometimes it is hard for people to figure out why they are upset/angry. The real thing they should try to do is try to not take their anger out on others. When one thing pisses you off don't take it out on the next person to cross your path.

That's what I'm saying although you should know when you're hungry but don't take out your irrational anger on your SO

You don't have to take out your anger on a person, but expressing your anger to your surroundings is what most people do. Keeping it inside can be worse