I feel very much the same about the "Hallmark Holidays", the recently fabricated holidays where people are guilted into sending cards and/or token gifts. I'm generally pretty thoughtless about gift giving. If I see something that I think someone should have, I tend to get it for them without thinking about it too much. If I'm lucky, it'll synchronize with a traditional gift giving occasion. On the other hand, I tend to have a hard time getting someone a gift because I'm obligated to. Just as gifts are hard to get for me, because if I want something that someone else could afford to get me, I've probably already gotten it. (I do tend to keep a list of stuff that I'd like at http://www.red4est.com/lrc/want.html because people have long bitched about this trait of mine) In the same vein, if there is something that I want to get for someone, I'm likely to do so whether or not there's an obligatory occasion coming up.
Perhaps the worst Hallmark Holiday is Valentine's day. I don't have hard numbers confirming it, but I've heard a lot of anecdotal evidence that relationships that get torpedoed on Valentine's day outnumber relationships that do well on VD by three or four to one. The biggest cause for this is mismatched expectations. One member of the relationship considers it to be an important symbolic occasion, the other doesn't consider it at all important. The first person then equates the lack of fuss with "you don't think I'm important" rather than "Valentine's day is not important". The other case is, when one person thinks that the relationship is much more serious than the other and the mismatched expectations bring this difference out into the cold hard light of day.