An important lesson - Do you clap?

When somebody has just finished presenting something or concluded a performance, do you take that little effort to clap for them?

I've been thinking about this all day. Last night, I went to go see some acrobatic performance. It... Wasn't really as good as I expected. Most of the audience (including me) didn't clap at the end. When the performers bowed to us they looked quite sad. So I called up an old buddy who does many solo musical performances and asked her if she claps. She was pissed off at the question but told me to always clap for a performance even if I don't care and even if the performance is shit.

I don't do presentations usually but if I didn't receive any claps or cheers I'd really feel like a pile of crap. (And be quite depressed for a bit)

From now on I'll take that small effort and use it to clap since I'd want the same thing if I were on the stage. I also am beginning to realize that other people actually matter, instead of just caring about myself all the time.

If you don't clap, I'd appreciate if you'd do so. It doesn't take anything at all and it's only effect lightens up somebodies mood.