it's certainly not OK to take it out on innocents around you, particularly those who love you. The lesson in the movie is clearly that treating your family like punching bags when you get angry is a bad thing. Max obviously (to a grown-up eye) learns this lesson, and the story just seemed unresolved without him acknowledging it.

Not trying to moralize too much, I think an apology would have put some punctuation at the end of the sentence, so to speak. I think the film itself would have benefitted from that punctuation.

See it for yourself and please get back to me with your impressions.