Rodney Dangerfield: You can't trust doctors either; they're all mixed up.<quoted text>
Ugly and stupid.
Johnny Carson: You really think so?
Rodney Dangerfield: Yeah, my proctologist used to be a photographer. He took X-Rays and told me to bend over and say 'Cheese.'
Johnny Carson:[uncontrollable laughter].
See the rest of the routine on the Tonight Show clip here: