I bought a rear light a few weeks ago and fixed it to my bike. When I got home from my next ride I noticed it was missing, it had fallen off somewhere - I wouldn't mind, it wasn't even dark when I went out.
The console from my cycle computer has flown off its cradle a few times when I have been out riding, but so far I have always managed to retrieve it before it gets crushed by a passing vehicle. I often lose that at home too, I put it down somewhere and my wife moves it.....she always denies it and then moves it back to where I put it - thinks she can fool me, huh - then I find it later.