I didn't have a lot of friends growing up, so that ment I spent long period of time alone. Within that time, I would get bored and just start day dreaming. A lot of it starts as a "What if...?" question. Now as an adult, I still don't have much of a social life and my job is meh, so I guess I still day dream a lot.
The down side is, my brain seems to go much faster than my drawing abilities, so I have ideas but can't draw fast enough to get them down. Maybe I should try to write them down...I dunno.