[scott_s]

Have you ever been in a bar at closing, when they turn the music off and the lights back on? It's a stark moment: Oh, right. This is reality.

I can't say that the sibling comments are wrong, but I don't think that's the real reason. Bars (clubs, really) do it because it fosters a feeling of unreality. It makes being at the bar different, and you feel different, and it's (supposed) to be special - it's a party. People show up because it does not feel like normal life.

Personally, the practice drives me crazy. As I intimated above, bars that do this are really clubs at night. I prefer places where a group of people can sit around a table and actually talk over some drinks.