I really don't "do" holidays at all. I ate a normal dinner on Thanksgiving - the Turkey Trot in the morning and, with no work, spending an afternoon with my kids being the only variations from a typical Thursday. This is true of all holidays, even the one my birthday falls on.
It started with growing up as a Jehovah's Witness. Holidays were not celebrated. Religious ones were pretty much considered corrupted with pagan rituals, commercial focus, and not directed by God to be observed. Secular holidays were putting too much focus on man rather than God. Birthdays were ... well, the only Bible ones involved very bad things happening (such as having John the Baptist beheaded) and promoted selfishness. The only celebration was the annual Memorial - following Jesus' command to "keep doing this in remembrance of me" applied to the passing of the wine and bread. It is done annually rather than at every Mass and only those considered amongst a special group of followers partake.
Even in school I was supposed to pass on the holiday activities and ask for non-holiday alternatives. Supposed to. Is it sad that I can remember making a pilgrim outfit in 2nd grade after assuring the teacher it was my decision, and knowing I couldn't take it home or wear it where my parents could see me?
There's plenty of other similar memories around holidays, such as getting yelled at for peeking out a window at Trick or Treaters because that made them come to our door, and sneaking out when we were supposed to be asleep to join the neighbors out setting off fireworks.
So, what do I remember of Valentine's Day? Very little. The class version I couldn't go get cards to pass out, so I had to have my name scratched from their lists because it wouldn't be fair. That meant I sat and wrote or colored while the other students decorated their bags, I suppose.
What I ~DO~ remember is my mother marrying her 4th husband (one of many in line at the City office for a civil ceremony), the reception to be held in a local park two days after. On the morning of the reception, running errands with the EX, I started having contractions, and we stopped by my mother's house. She timed them ... and off to the hospital we went.
So instead of being in the park, I was across the street at the hospital giving birth to DS - with various family taking turns coming across to visit the newcomer. (None of my labors, at least the hospital portion, lasted more than an hour and change.)
Later years saw me buying little stuffed animals for the kids, mostly, but without any super focus that we HAD to do something for the day.
In fact the most recent memory I have is from around 6 or 7 years ago. I'd gotten into the habit of buying flowers weekly from the local CostCo. Good price and I liked having a vase sitting out because it brightened the room. Then a couple weeks before Valentine's Day it felt like the prices tripled and the quality dropped.
I was disgusted and quit buying flowers completely.
So ... the most memorable part of this day to me? My mother marrying #4 and hating the floral industry's greed on this day.
What I tend to do instead is pick completely random days to "celebrate" things that are important. I have a friend greeting card I picked out to mail to my best friend - and wrote "Happy Bestest Friend Day" in it. Every day is Happy Bestest Friend Day. Every day is Love My Children day. Ditto for gift-giving. I do it spontaneously whenever I have the means and know something they'd like.
So don't feel obliged to celebrate this day or to follow some imaginary rules for how it should be celebrated. Sure, let those you love know you love them - but do that every day you think to do so.