What are some humorous one-liners?

One example of a one-liner joke is, "The first rule of holes: if you are in one, stop digging." Another example is, "Don't sweat the petty things and don't pet the sweaty things," spoken by George Carlin.

Another one-liner joke example from George Carlin is, "Would a fly without wings be called a walk?" Many one-liner jokes are questions that don't have answers. Other one-liner jokes are, "A computer once beat me at chess, but it was no match for me at kick boxing," and, "A bank is a place that will lend you money, if you can prove that you don’t need it."