How important is it to have friends?

I hope it's not too important, because I only have a few friends, but I always have trouble with them... The trouble is that my friends and I always grow apart. They forget about me. This has happened with every single friend I've had, and I can feel it happening with the friends I have now. I know this is just natural, but I think I'm destined to be friendless. I don't have trouble talking to people or anything and I'm quite friendly, it's just that people easily forget about me. And I never forget about any of my friends, which sucks because that means I'm the only one hurting... So now I've basically given up on having friends. If they forget about me, then so be it, I'll try not to let it bother me. But is it bad to be this way? You always hear about the importance of friendship, so I was just wondering... What do you think?