Valentine's Day is a farce. A fake. It's an entirely manufactured, prepackaged, corporate excuse. It's a fiction designed to get people to buy cards, flowers, candy, etc. It's not celebrating anything. There is no objective reason for it. If you're in a relationship, you should show your love 24/7.
Meh. You could say the same about Christmas and the festive spirit (or religious significance if you are into it), Independence Day and patriotism (or your particular national holiday), etc. Of course it's fake and you should be doing that all year long. But humans are creatures of routine, and yearly festivities are a big part of our social behaviour, so no getting over it.
I'd counter that by saying that at least Christmas and Independence Day have roots into something. Christmas being the celebration of the birth of the Christian Savior Jesus, Independence Day the celebration of America getting its independence from England, Halloween for All Saint's Day, Thanksgiving is a celebration of family and the fall harvest, New Years the celebration of the new year, Easter the death and rebirth of Christ, yadda, yadda. All celebrations of some recognisable and tangable and all Holidays without roots in comercailism and though many are far more commercailized today they still have their simpler beginings and the spirt of what they are to some degree still remains.
Valentine's Day? A celebration of buying your girl flowers and chocolate. I mean, really, what are we supposed to be celebrating with this day?