Why do people keep antiques

I hate clutter; my husband is a pack rat. Recently he saw his father, who is also a pack rat, and he told my husband that once he and I settle down someplace, he'd like to give my husband some "valuable" things he's collected over the years. His father insists these things not be sold, they are for keeping and passing down to our children. One of the things that he wants to give us, for example, is a set of old guns. My father in law has never used them, he acquired them years ago and they are collecting dust in a closet. I don't like guns. Now you people who do like guns, don't get into a huff - I have no problem with other people having guns, and my father is an avid hunter. I was practically raised on venison and wild turkey. But I don't want guns in the house. My husband has never used one in his entire life; I have and don't care for it, and I have terrible aim. Us having guns in the house seems at best, a waste of space, and at worst, a potential safety hazard. My mother started this recently also; she gave me a very ugly tea cup and saucer that she feels is "valuable," and a piece of Lenox (not my taste) she's had for decades that she wants me to keep. I didn't want these things, but of course refusing them would result in hurt feelings. I'd feel guilty throwing them out, selling, or donating them. What to do?

Why do people collect these things? Neither my mother nor my father in law are particularly old, they are not dying anytime soon...if they like these things so much, they should keep them. I don't even own a house yet, and already I am depressed at the amount of space being wasted on other people's junk.