Stupidity and sarcasm

Here is something I noticed today, crossing many streets this morning as I was walking from home, all the way to Piccadilly Circus:

You know when you go and push the button at the pedestrian crossing. PLEASE tell me why, even RIGHT after I push it (and people around me see me push it) do the same people feel the need to push it it again?

We are all walking the same way across the same crosswalk. Do they not think I know how to push a simple button correctly, so they push it again? Same scenario applies to lifts (see above).

If the floor you are going to is already lit up, why push it again? I know it is probably just a habit or human nature, but still. It annoys me. Please enlighten me....