You think to yourself "Hmm, Im actually getting pretty good here!" and then you go to say, guitar center, and there is some dude there who just rips your face off!
I guess being good is a little bit of a subjective thing, but as far as musician vs. musician, I dont stack up like I thought I did.
Of course, thats not why a lot of people start playing, to be "better then" the next guy. But one can't help it after playing for the better part of a decade to begin to compare. But I can also really appreciate other musicians and learn from them.

But aint it a bitch getting those little "humbling" moments!