Why are some teenagers more susceptible to changing emotions?

Well teenage years are very hard because it the time of your life when you have to make some serious decisions, and if you screw up then it could get very hard for them in their near future. So the reason they're susceptible is because they have a lot on their mind, and they have to carry a huge burden. And normally people think of teenagers as a problem because of their moods, but it not their fault that they can't keep their emotions steady. Its probably just because the parents haven't taught them to be mannered.

I'm not saying its the parent fault, its just maybe the parents need to teach them how to be more mannered. And if you have already tried that then maybe love on them, and tell them you care about them (= Maybe giving them privilages like allowance, and try and trust them with responseabilities. LMK Let me know how that works out =)