I've never put a sticker or decal on an instrument, though I've bought a couple that had some (which I removed.) I don't even have a bumper sticker on my car. But I have a bass that's such a plain jane that I'm considering slapping just one lone decal on it...I actually have a huge collection of them going back to when I was a kid in the early 70s... Maybe I'm just tired as hell...such a minor thing, really, and easily removed if I got sick of it. I generally think it's not my thing, but I dunno.... Anyone got any stickered-up basses to post?