Two bad experiences:
1) My wife had a lymph node removed - literally a 7 minute operation. About 2 total hours at the hospital (outpatient, ofcourse) plus lab work. We failed to ask how much it would cost ahead of time thinking it couldn't be more than $1500 tops. It cost over $15,000 !!! Impossible to justify.
2) I went to the emergency room one Sunday last year after a mountain bike crash. They cleaned out some wounds. That turned out to be very expensive too, for what they did ($1200!!). Worst part is THEY SENT THE BILL TO THE WRONG ADDRESS (thought my insurance company was taking care of things) even though my correct address is all over the paperwork. They never called or e-mailed me. I found out while re-finiancing my mortgage that they sent the file to collections. And they didn't even apologize.