What is the main reason for boxers saying delusional things all the time?

Out of all sports, boxers (and their trainers) say the most delusional things. Now, there are several factors that contribute to this but I want to know what you all think is the biggest reason for it: 1. To be a great fighter, you have to have irrational confidence and be a little bit crazy to even choose the profession in the first place. 2. Boxers mostly come from poverty, and besides certain exceptions, have little to no education. 3. Years of boxing and sparring, taking hits to the head, cutting weight in unhealthy ways, cause brain damage that is apparent when they open their mouths to give answers. 4. Boxers don't have a league that promotes all of them so they are taught to say things for attention and constantly self promote.