I own a pretty decent set of Henckel's International knives (high end of one brother imprint). Not having yet had an opportunity to borrow really high end knives from anybody, I suspect they're the best knives I've ever used, and they're certainly the best I've ever owned or had regular access to. So I try to take good care of them. I hone them occasionally, I don't sharpen them with a home sharpener, I make sure to only cut on wood or cutting-board plastic, and a knife is either clean, dry, and in the block, or is currently in use.
Because the knives are good and pretty expensive, and I don't want to have to worry about how other people might be handling them, I have a standing request with my housemates that nobody use my knives, and I keep them in their own block in a somewhat remote part of the kitchen to make that less burdensome to other people (there are house knives, kept on a convenient magnet near the stove, with a wall-mounted manual sharpener nearby).
I just went into the kitchen to discover my chef's knife sitting in the sink with a cutting board [a nice wood cutting board of mine, and that's a separate but related rant, actually] and a prep bowl filled with whatever was in there and water.
I'm not pissed yet, because I don't really get pissed these days, but . . . seriously? You [allow your friends to] use my knife after I've explicitly asked you not to, and you [allow your friends to] leave it lying around dirty and wet? Do you simply completely lack any respect for others' property?
It's bad enough that it was left sitting in the sink, but should I be worrying that when I'm not around somebody is sharpening them, putting them through the dishwasher, or even cutting on glass? I mean, seriously, a complete stranger is using my good tools when I'm not looking; I don't actually know what they're doing to them.
[Edit: Of course, it could always be a simple miscommunication where somebody didn't get the memo, and I could be overreacting.]