Auron's fault?

[Pete for President]

But Auron knows that Tidus being arrogant is the least that matters in the whole plan. Sin needs to be destroyed no matter what, and arrogance is somewhat related to confidence.

I should've been clearer. Auron's not deliberately trying to build him up. It's just how Tidus interprets it because Auron is a wise man and whose words should be listened to. It's like, if you met a guy in the street and he gave you some advice and then he got mobbed by paparazzi before escaping in a limo, you'd probably pay more attention to what he said. I guess xD

Ah, point taken. Auron has been sort of his mentor-ish figure in Dream Zanarkand, after all.