I agree with Trp that people can do whatever they want - it doesn't affect me, doesn't stop me having a nice day, but what pisses me off is when people in shitty relationshis (or who you already know can't hold one down) go on about how amazing their relationship is, and how amazing their partner is, because they were gifted with the entirety of the Card Factory.
I think I spent the last one in London with my mum (who clearly doesn't celebrate either, or she'd have spent the day with dad), and her friend from work, and her sister. W all went out for a meal and then for drinks and I for one had a great time, totally single.
This will be the first one I'm not single for, I guess. Another relationship came close to the date, but I fell out of that one and didn't see the point in hanging on JUST to not be single on V-day. That was the London day, actually.