Eih. Low. You'll get emotionally involved every now and then but it's like the guy who works at Baskin Robbins where, after a while, the thought of ice cream just makes him sick. (Think hard about this concept if you're also considering a career as a gynecologist.)
The bigger stress probably won't come from clients you have to turn down because they aren't qualified, but rather from back pressure in your bank pushing you to get GOOD candidates to whom you can write loans. The good ones are always hard to find.