Applause: A mysterious Art.

Humans act strangely. If you think about it long enough so many of our behaviors begin to seem odd. Take clapping for example. Why is it that we think that beating our hands together is a manifestation of pleasure, recognition and  praise. Recently during a theatrical performance I attended I was thinking about the strange art of clapping. The theater was full of people slapping their hands expressing their approval of the actors on the stage. I guess it is just me thinking about it too much but I was imagining someone seeing a crowed clapping for the first time. Who would guess that this sound being produced by these strange people banging their hands together was a manifestation of pleasure? A most puzzling manifestation of this odd behavior is in the movie theater. Why do people clap when none of the creators are there to hear it?
What is more amazing (and I think that this is one thing that truly distinguishes humanity from other animals) is that humans can use clapping to express displeasure. The ability to clap ironically is a singular feat. Some one stumbles or fumbles and clapping could now to be used to express mockery and disapproval. To an outside observer unfamiliar with clapping this must be singularly confusing.
I don't know why I think about these things. I was just wondering how it happened that people started clapping. I wonder if ironic clapping came first. I imagine someone making an idiot of themselves and their friend finding no better way to express his jubilation than to beat his hands together from pure excitement. Of course I just wonder who was really making a fool of himself.