Had a friend who did a lot of Unix stuff, and was working on his Master's thesis in MS Word for 3 or 4 hours without saving... he was into the flow, and getting a few wires crossed, hit CTRL-W to delete the last typo'd word he'd written. He was reminded that he wasn't in Unix when a message popped up asking if he wanted to save... thinking that, no, what he really wanted to do was get rid of that last word and finish his sentence before he saved, he clicked 'No', then watched in horror as Word closed - taking his thesis with it.