I can't sleep during the day.
When I visited Spain for a holiday a while ago, I'd sleep until about 11:30am, get up and have breakfast, then kick back for siesta. At about 3-4pm I'd start the day, ass about until about 9-10pm. Had dinner around midnight and then off to bed a bit later. It was great.
The only bad part was if I needed to go to the shops and I slept in (to say midday or so), by the time I got to the shops at 1pm or 2pm they were all shut.