I'm going to post an example of why I sometimes crop (and looking at my gallery, I don't do it very often) .... 

I'm going to post my original thumbnail for one of my images, then the image, and then what the thumbnail would have looked like had I just left it on automatic.

Many of you will disagree with me, of that I am certain, but I do not see the original thumbnail image as being anything more or less than a highlighting of my central character.  And, further, I happen to think that the original thumbnail gives a better impression of what I hoped would be the nobility of the character.

I, for one, think that gets lost in the thumbnail sized as it would have been had I left it uncropped.

Could be worse, could be raining.