I used to get upset, but as I have got older I have started caring less. I was 30 2 weeks ago and a few people forgot that, but then other people remembered who I didnt expect to. Some people are just not great at that sort of thing, try not to take it personally if it happens.
My friend I`d known since school fogot mine. Her excuse was the best I`d heard , I bought a lot of cards but couldn`t find one suitable for you so it slipped my mind after that.