So did my dad (and he would if he had the strength today). I remember that he laughed at himself sometimes; he once had a ceremony when he threw a white "weekend work" t-shirt that had more holes than fabric left. It was that big a deal. :)
I have a hard time throwing things away too, though I don't come anywhere near my dad's level. It's mostly sentimental stuff that is hard for me to give/throw away.
However, when my husband cleans the house, there suddenly seems to be a lot more space, and though it's very tempting, I try not to look in the huge filled garbage bag. :)