I think that is one of the major reasons why many art folk are afraid to exhibit. They might not be showing the work because it is not of a creative quality a gallery/curator thinks is important. The second reason is the one listed above. Putting your heart on a wall, your innermost feelings is tough, sort of like walking naked on a city side walk, everything is hanging out! :)
I think that's one of the reasons most artists say bad things about their work BEFORE they show it to you (this is bad, this is not the final version, I was only practicing etc), sort of a defense mechanism. Another thing that happens is people go into techno talk. They speak of cameras and lens, filters and shutter speeds, they do not allow the viewer to feel the emotions of the work, soak it in. It is just because the artist feels uncomfortable letting the print stand on its own. I am guilty of some of this defensive talk.
Many photo/artist folk are also extremely sensitive to any kind of criticism. I have had that problem in my photo club history. When I gave too honest OPINIONS, people freaked out, especially the older club members who are much more set in their ways. Older people tend to be more sensitive especially when you point out the obvious truth, a truth they may have been hiding from.
The truly brave artists create what they feel is right, dismiss criticism easily and have no fear of showing their emotions on any gallery wall. They listen to opinions of others then brush it off, they show all work without fear of being too open and honest. I feel I have traveled partly down the path of the brave artist, I still have a ways to go. Hopefully that courage and honesty will develop with time (pun intended) :)).