As I said I do know the feeling as I am the same, so I do understand. I'm sure I am the worlds worst for picking holes in my own work. But all I am saying is that you should try and remember that where the artists sees what a photograph could have been, the viewer sees what it IS, which is a point of view an artist should try and see from time to time.
I'm not saying you shouldn't feel that you can do better, just that you should try and use that voice saying "could have been better" in a positive way and use it to highlight the things about your work you would like to expand or improve.
I'm sure you already do, I just don't like to see a talented artist feeling bad about their work.