I don't understand why some people are so arrogant...:(

I recently got into a quarrel with a Britisher on italki...and I know I didn't show respect, and I'm really sorry for that...
But it's baffling to me why some people are so arrogant...when he had nothing to defend himself with, then he showed off how many amazing experiences he had had. He said that he'd worked in three different countries and in the field of languages for so many years....aww...a person who only understands 5 five languages showing off? Maybe most people cannot speak so many languages as he does, but at least they have very good attitudes...
I always think that keeping on learning is the best way for me to fulfill myself, because many other people can be way better than I am...and that's why I am learning languages, maths, biology, and history, all by myself currently...because I don't wanna want to fall behind.
Although I wasn't born with a silver spoon, and now I live in a slum with my family,but I don't think I know less than other people do...Not havin' having been abroad doesn't make a person a primary school student !!