Books - Chances of me reading the same book again are slim. But it's really hard to let go of them. I now own an e-reader, but even if I could get all of those books on it (which seems impossible, if not very expensive and for no good reason), I would feel something missing. Then again, they do take much space, gather dust and are likely to be left untouched.
Gifts from people - whilst I can relatively easily throw away stuff I bought, it's so much harder with gifts people gave me. It almost feels like betraying them.
Any practical or (pop)-psychology suggestions on how to get over these hurdles?