"If you want to make an audience laugh, you dress a man up as an old lady, then kick him down the stairs. If you want to make a comedian laugh, it has to be an actual old lady.
"
--W.C. Fields, A variant on this was attributed to Fields by John Cleese in a 2014 interview with Adam Savage. Another attribution appeared in the NY Times 24 Jan 2012
The difference between genius and stupid
The difference between genius and stupidity is that genius has its limits.