People Who Borrow & Forget

I hate lending things to people. Almost always, the person who borrows something from me forgets that he/she has it. Then I have to be the one who reminds them - and of course I have to do this politely so as not to offend the person. Why do people borrow and then forget? Is the same type of person that is forward enough to request something also automatically the same type of person that won't care about remembering to return it?
I find it really disrespectful when people borrow and forget. If I decide to give you something, so you can watch it, read it, or use it, don't put the additional burden on me to remind you politely that you have it!
For me at least, when I borrow something (which I do very rarely and only as a last resort - bordering on an emergency), I not only remember to give it back but I make sure to return it as soon as I possibly can. This not only shows respect but also gratefulness - and it makes the person more likely to lend again if I need something. Don't people realize that they are hurting their own reputations when they forget to return something?
What is even worse, and this has happened to me several times, is when the person I lend something to either damages it in some way (and pretends like that's the condition that they got it in) or passes it onto someone else (and then can't remember who they gave it to).
What are these people - simply forgetful, pure assholes, mindless, or overall just moronic?
I know that in a sense it's my own fault, since I decided/agreed to lend the item. So to solve problems like these once and for all, I'll attack the source of these recurring instances and simply start a personal policy of not lending anything to anyone, ever. If I'm in a situation where I really seem to have no other choice, I'll have the person leave something of theirs with me, like their ID or firstborn child. And to those who love to borrow: please get your own stuff! If I have it, you can also get it - so please don't place the double-burden on me to not only remember that you have it but also have to remind you to give it back.