Why does my ex brag to me?

The ever few times we run into each other, all he's done is brag. Just recently, I saw him out and about while I was with some friends and I asked him a question and he spent all this time telling me of where I should go and how much money he spent at however many places and never really answered my question. I didn't want to know where he had been or going, although i was fine hearing it but why can't he be normal? What do guys try to accomplish by bragging? I don't understand.