We all do it, some more than others, old people less than young people, women differently than men. Daydreaming. It can make you forget your current situation, and let you live out your fantasies.
There is certainly a negative aspect associated with daydreaming, with people in the past even warning parents not to let their children daydream, as it may lead to negative consequences such as psychosis!
But if everyone daydreams, than logic dictates that surely there must be a function to it. In short, what is the science behind daydreams?