"I luv to laff"

I noticed, while listening to someone try to explain their reaction to seeing a stupid drunken antic, that one of the most difficult (if not the most difficult) things for humans to describe is laughter. How much easier is it to understand, "she sang like Judy Garland," than, "I laughed until I wanted to cry"? With laughter there seems to be no reference point; there is no common understanding of what a good laugh is (unless perhaps you cite Mary Poppins' uncle).