The first surgeon said, “I like operating on librarians.  When you open them up, everything is in alphabetical order”.

The second surgeon said, “I like operating on accountants.  When you open them up, everything is numbered and organized.”

The third surgeon said, “I like operating on electricians.  When you open them up, everything is color-coded.”

The fourth surgeon said, “No no, operating on politicians is clearly the best, and also really easy.”

The other three surgeons looked at each other in disbelief.  One of them asked why.

The fourth surgeon replied, “Because they are heartless, gutless, spineless, and their ass and head are interchangeable.”