I wouldn't have believed it, but I'm pretty close to becoming one of 'those' hoarders. Except for the dedicated freezer, I'm nearly there.
1. I hoard because something is about to become unavailable.
2. I hoard because I'm tired of running out of a particular film, and want more than 20 rolls on hand.
3. I hoard because something's on sale and I'm an idiot.
I don't hoard chems, exactly, I just panic-buy when rumors start to fly. See no.3 above.