There are as many opinions as there are experts.
—Franklin D. Roosevelt
If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.
Expert: a man who makes three correct guesses consecutively.
—Laurence J. Peter
An expert is a person who has made all the mistakes that can be made in a very narrow field.
I know a lot about cars. I can look at a car's headlights and tell you exactly which way it's coming.