Honestly, childhood stuff such as the boxes of character valentines to pass out to classmates, choosing the candy to hand out along with it, collecting piles of pink and red sweets. Or something such as the year I had an ear infection and, to make me feel better, my mom baked mini chocolate cakes in heart shapes.
I guess I like the fun, lighthearted aspects of the holiday. Romance is certainly nice too, but Valentine's Day doesn't necessarily stand out as the most romantic time of year to me. So, stronger are the associations of hearts and teddy bears and funny sitcom episodes and boxes of chocolate.