Are most jokes about how stupid people are?

[Manish]

Just been wondering recently, as I hear the usual jokes when friends gather, or at a party. Most jokes are really made to show how stupid one (or more) characters in the story are. May it be blondes, or anyone else. When a joke's story has one person replying with a sharp, quick-witted answer -- people don't laugh at the sharpness of the reply, but they laugh at how stupid the other person in the story would be looking/feeling right now.

Is that what most jokes are all about?