I wonder

I wonder why there's someone has a personal instability.

I Wonder why, even in his adult phases, he actually acts like a child

I wonder why, even with the person he is not really know, he can angry easily in his bad mood,especially.

and I wonder why, there is a person ,which he angry with, still can respond normally.

I mean that person still can apologize him without the word "sorry" never come out from his tongue, (even he has done it a hundred times), and that person just wait untill the cycle re-rotate.

Through the temporary good mood phase,then switch to bad mood phase.

and the man mad of that person again..(with no reason)
and it seems to be so scary.
But that person just keep silent, try to get a positive think to make what he's done seems rasionable.

if i were that person..
what would i do?