I think it is interesting to hear the top professional poker players' perspective on busting out of tournaments. For the most part, if the player believes he/she played well, they are content with where they've cashed. If the player believes he/she did not play their best poker, they are not content, even if they had a big cash.
I recently saw an interview with Bryn Kenney, where he was not pleased because he had "only" min cashed in a few of the Poker Masters' tournaments. Even though he had played well, he believed he could have played better and finished higher. I think it's inspiring to see that the best of the best continue to strive to improve their play.