absurd & surreal

For a long time now, my favorite type of humor has been absurd and surreal humor (though I dislike the vulgarity and profanity found in much of it). Some examples of the more famous of this type of comics are:

Monty Python
Douglas Adams
Mitch Hedberg (whose jokes I collected earlier)
Homestar Runner

and here are some examples of absurd jokes:

Two fish are sitting in a tank, and one turns to the other and says, "Do you know how to drive this thing?"

Q: What do a grape and a chicken have in common?
A: They're both purple, except for the chicken.

Rice is great if you're really hungry and want to eat two thousand of something.

But recently I've started to have a sneaking suspicion that there was something not quite right about that kind of humor. Today I found the Wikipedia entry that pinpoints why.