Normally when I'm dj'ing (in the techno/club meaning of the term) I'm the one choosing the music, the styles of music I choose represent the kind of dj I am. The worst thing you can do is come up to me and ask me to play a specific song or a specific genre. Now if you're familiar with the DJ, his style of mixing, the artists and tracks he likes, then you're allowed. I asked a dj if he could play a particular track that he had used in a mixtape, that was my favorite track at the time. He happily agreed, and proceeded to open up his set with that track!
Anyway, my point is that dj'ing at a wedding is not at all like this. I spent hours gathering tracks from albums and artists I'd never heard of that were favorites of the bride and groom and best men... Even though probably less than a quarter of that music was used. I had people coming up to me left and right asking for this track or that track. One girl came up with her CD binder, and wanted me to play several tracks off some CD she had burned. I have no idea of knowing what's on there, if it's recorded at a decent quality... so you just have to give it a try. One guy had no reservations expressing unhappiness that I didn't play a track that he wanted. But when the time is up, the time is up, I must pack up and go home!
Still it's interesting and fun to see the young and the old gettin' their groove on. It's a different kind of intensity, playing for the slightly intoxicated as opposed to the smashed out of their minds...