Thanks for your comment.

I think you may be right about the intention of the movie. But, my personal take is that if he had learned to be a mature person capable of communicating with the people in his life, then the movie wouldn’t have ended with him leaving without telling his friend.

Yes, I know they had foreshadowed that moment with Ben Affleck’s character saying, “one day I hope you’re gone,” or whatever he said. But it’s still ridiculous. Why not have a beer and say, “hey man, I’m taking off tomorrow, I’m going to do that thing you always said I should do. Let’s celebrate.” That would be an adult thing to do.

It’s a really weird premise that after all he had learned about navigating a world of adults, he still adhered to the childish promises of the past that involve a complete lack of mature communication.