Marion, after ruminating a bit more about what you wrote, I thought I should come back with this. You said:

"I'm worried about what it says about me if I can look at a person in pain and see a character."

That is what sets you apart as an artist though. It is a bit of a burden to bear, but hey--nobody in life gets off that easy. Artists can do that, regular folks can't. That is why society is uncomfortable having artists around. Artists hold the mirror up to society. Or as Kurt Vonnegut put it, "artists are society's canaries in the coal mine". Now, if you work in a coal mine, the canary is a creature you always want near you, because they keel over and die when the gases start to build up to levels that will kill you. They warn you that it is time to save yourself, and get the hell out. But you can also understand the discomfort with the messenger--it isn't that easy to love someone who makes you feel that threatened, that vulnerable, that humanly frail.

You also said:

"Having said that, now that I've put my concern into words, it seems a little absurd: if you're worried about being callous, then you're probably not, eh?"

Weeelll...I'm afraid we can't get ourselves off the hook that easily. Actually, you can still be callous, even when you are concerned about being callous. It is probably more likely though, that we worry about being perceived by others as being callous. The latter circumstance actually helps keep us more in check. But it also makes us more manipulative and deceptive, when we want to get trick others and ourselves, to get around that pesky, nagging thought about our own callousness.

Like I said, no easy answers for artists. Which is why most people don't become artists. Too much contradiction, paradox, ambiguity, etc. for most people to be comfortable with even occassionally, much less as a way of life.