I don't shoot professionally, but my understanding of even photographers like Joe McNally for example (not to pick on Joe but he has shot for Life, NG, etc.) is that there can be a difference between what the photographer shoots and what the client (magazine editor in this case) wants. It may be the photographer's favourite image, but if the client doesn't like it, it's not going to get used.
Now if you're not shooting for a client, then the client in effect is you. And here we open a whole other can of worms, because everyone gets an opinion on what they like and what they don't like. Therefore it's difficult for me to say what's a good shot and what isn't, only what I think is a good image and what isn't. Your opinion may be entirely different. There's a saying, "I tried to teach you to be yourself but find that I cannot. I can only teach you to be me, for I am the only model that I have."
Generally speaking, if someone posts an image that I don't like I don't say anything, because to the next person it may be great. Conversely, if I like an image, I'll usually let the person know. Really, though, all I'm saying is that I either agree with your vision of a particular scene or I don't. The first reaction happens at a visceral level, and from there I can probably extrapolate what it is about the image that works or doesn't work for me. Sometimes I'll see something else in an image than what's presented, and in those cases I'll often offer a suggestion such as, "If it was my image, I'd..."
The hard part for me as a photographer (and others have expressed similar sentiments) is separating myself from my images. If it's an image that is important to me because of the story that went into making it, other people may or may not see that story reflected in the image itself. In my opinion every image has to stand on its own two feet, so to speak, without background, title, etc. It may be useful to have a context to associate with an image, but that to me is secondary. The image either makes it on its own or it doesn't.
Some of the 'more experienced' photographers here have shot from the perspective of having eight exposures on a roll of film, or using single large format plates, and with that background I think we tend to be more critical of a scene before making an image. I shoot many, many more images now with digital than I ever did with film, but I still try to be ruthless with my own work. And sometimes I fail! IIRC, photographer Dewitt Jones was asked once about his 'keeper' rate, and his response was essentially that it doesn't matter how many images you make or how many images you keep. All that really matters is, did you get the image you wanted?