Wow, some really ouchy stories. In particular, the fact that some people acted as though it were not even important enough to try and 'make straight' for.
Maybe eoe is right, and it is about how you are raised. We never had much, but you took care of anything you had, or was borrowed, or even touched you. If you didn't, you lost things at the snap of a finger. Can't take care of it? Well, off it goes to charity or someone else.
I still carry that with me.
Respecting things, no matter who they belong to, is a way of respecting yourself.
I get very upset when someone is careless with my stuff, so I am now careful who I loan out to. Everyone gets one chance; and I try to start by loaning little things. Kinda strict, but it is a bit of a matter of trust for me.
If you throw wrappers on my floor rather than putting things in the garbage, chances are I won't lend you a nice thing. It keeps me somewhat sane.