The hours blow during residency - you're always tired. I don't know if this applies stateside - I'm in Canada and there's no 80 hour rule. We just switched to a night float and my life got ridiculously better.
Adult spine clinic.
Arthroplasty rotations after you've done a few, remembered how to do them, and remembered why you have no interest in putting in joints when you're done.
Turning into an ******* when on trauma rotation (aka "trauma rage").
Over-specialization. I would have loved to have come through 20 years ago.
Old-school staff guys and their knuckle dragging mentatlity.
HOWEVER - I love my job.
Being tired isn't the same as being rich, but most times it's close enough.