The title is kinda harsh, but hear me out. I was talking with a fellow photographer and we came up with this theory, there are always exceptions though so keep this in mind.
The theory is this: As a photographer, if you are in love with your work and think every photo you take is pure gold there is a strong suggestion that you're really not that great. Whereas if you don't like most (if any) of your own work then you are actually quite awesome.
Of course there are some people that take crap photos and think they suck, and there are also some people that take amazing photos and they know it... they are the exception. I'm talking about general masses here, I have seen far too many photographers with underexposed blurry photos that are over photoshopped and (in my opinion) are sub par images that think their work belongs in GQ and on billboards. On the other side, I have also seen photographers that take AMAZING photos and always find something wrong with them.