You can't throw away those 150 postcards your dead great-aunt wrote you because you feel like you're betraying her memory. It's the same with rubbish presents friends and family have given you over the years: you think you're proving how much you love them by keeping their dodgy gifts in the back of your cupboard.
Paranoia: Every single email, photo and letter you ever got from that hottie from the gym you had a fling with back in 1993? Why? Do you think people aren't going to believe you? And why keep that size 8 dress when you haven't been able to squeeze yourself into it for years?!