Okay, looks like I get to play devil's advocate here. Not to make another Studio C reference, or anything...
I think Valentine's Day is fine. Ahh put down the spikes. We have a specific day for people who like each other to express that. Yes, you can do that any day of the year, but same with Veterans' Day, or whatever your Independence Day might be, or Mother's Day, Father's Day...so on and so forth. You can express joy for your parents anytime, but we have one special day for each - besides their birthdays - where that love can be celebrated no matter who or where you are. A day when people can celebrate together. I see nothing wrong with that, nothing at all!
Valentine's Day is the same. You and your boyfriend/girlfriend/husband/wife/some-combination-of-the-above obviously don't love each other just on February 14th. Of course not. But it's a day when you can show it, a day to represent the meaning that another human can have in your life. Are you going to hate Veterans' Day just because you don't know anyone who ever served? I certainly hope you don't, or at least that you don't say so to people who do celebrate it...
Think of it like this. At least there's lots of sweet stuff. Yum. You don't need a significant other to buy and eat some candy!