@Evelyn Hmm, i think when a story is well build and I can see the effort that is put into the characters, i dont mind them acting this way. Sure, its annoying and as a "bystander" we are able to recognise their behaviour as childish or hypocrite as you said, but if we walk into their shoes and experience their emotions on daily basis it would make sense in some way (its not real, i know). 
Anyway, see it as a good sign, it annoys you because you care, because you see the potential in those characters and in the end of the day we root for each of them to find themselves.
Btw, that is why i like ML's character. He lived for so long and yet he chooses to act immaturely. He CHOOSES. It makes me wonder what happened in the past, and as i see it, its also the reason MC is drawn to him.