Four doctors who hadn't seen each other since their surgical residencies met at a medical seminar. Adjourning for dinner and drinks, they started talking about what makes a good surgical patient.
The first said, "Electrical engineers, because you open 'em up and everything is color-coded."

"Nah," said the second. "It's librarians. You open 'em up and everything is alphabetized."

The third scoffed. "Of course not," he said. "It's accountants. You open 'em up and everything is numbered."

"Lawyers," said the fourth, with a shake of his head. "It's lawyers, you idiots! No heart, no guts, no spine, and the ass and the brain are interchangeable."