We remember the birthdays, marriage days and some other big days of our loved ones and celebrate them accordingly. But along with those days, if some other days are reminded like where you are naughty or went mad of your partner for the first time.
Example: Imagine that you are traveling with your partner on a vehicle in a calm lonely colony at a romantic evening. The vehicle was troubled and it was dropped in that place and you both started walking holding hand in hand. You then came to know that your partner cannot walk for more distance. On the way, you came across a Tea stall, you went there for relaxation and had a hot tea and discussed more things where you both came to know a lot about each other.
Now recollect, all these are a result of the vehicle which was troubled, so you thus recollect the date and celebrate the occasion every year along with the same troubled vehicle.
Though it seems to be silly in the beginning, it will be the reason for your smile in the future when you think of it at your leisure.