"Pain of sex change" joke

Bob drops by a bar he used to visit when he was young and orders a drink. He hears a man call out his name but the only person at the bar is a beautiful blonde woman. Finally the woman walks over to him and says "Bob, it's me Ralph, your old high school pal".

Bob is completely shocked as he finally realizes that Ralph has had a sex change. Bob is curious about the change and asks Ralph if the procedure hurt much. Ralph says "not really".

Bob asks " well, when they pumped in the silicone for your breasts, that must have hurt didn't it?".

Ralph answers "no, that didn't hurt much". Bob asks "when they.. you know.. chopped off your willy, now that must have hurt!?".

Ralph thinks for a moment and says "no, that didn't hurt all that much. Bob is still curious and asks "well, was there any part of the operation that was painful?"

Ralph nods his/her head and says "oh ya, it REALLY hurt when they drilled that hole in my head and sucked out half my brains."