Literally talking to my DM about this right now. You have to grade on a curve but absolutely good, kind, even in control people can be barbarians. Frankly the entire self-limitation people put on themselves by forcing a class based on tropes is getting tiring.

Hell, I had an idea for a barbarian that doesn’t get bad but instead just locks in. Just goes real quiet and fuck’s shit up.

You can also make a paladin that doesn’t wear plate armour, who uses a bow, and who’s oath is to protect their village or simply they just love their wife a lot and it’s their wedding vows.

Nah, some people have short fuses, some have very particular things/scenarios that set them off. Just don’t step on their feet, and back them up if someone’s pushing their buttons accidentally/on purpose.