I reckon we're our own worst enemy when it comes to our own opinions regarding our own stuff. And let's face it, and this might be a corny cliche, but nobody's perfect.
Most of the time, I'm quite happy with what I've taken but I'd have to be in the right mood and right frame of mind for it whenever I think about taking and looking at my photos for one reason or another.
If I'm having a bad day or I've been in a steaming rush in them greenhouses all day and I come home all tired and irritable then I won't touch the camera as I know I won't produce good results (which does make putting together my 365 photo website quite hard work sometimes!).
But then I have my better days and whenever I take pictures, I do find myself actually admiring them, and thankfully that is much more often the case than not. So, yes, I would be utterly gutted if I ever had a hard drive failure and all my CDroms got corrupted at the same time and I lose everything in the process.
I have never thought of myself as a "brilliant" photographer but as someone who just merely enjoy photography and all the time I think I've developed my own little niche in the world of photography then I'm generally happy with my stuff. Oh, of course I do produce the odd dud photos (who doesn't?) and those are the one that gets deleted without hestitation.

It's a shame that it's only in the past five years have I got into photography big time, but that's only because of the relative ease and cheapness associated with digital photography rather than traditional film photography.
Actually, having said all that, I'm a lot more critical with my cartoons. Whenever I do a cartoon and finally place it on the internet for all to see, I find myself looking at it and thinking there would be room for improvements. I always feel like it's missing something or it's not "quite there" and even though I've drawn literally thousands of cartoons, it feels like I've still yet to produce that ultimate cartoon that I'm really happy with. But at the end of the day I put it down to an artist thing and don't let it get to me.