I'm sure it does bug some, but again, provided everything's in great condition (and he doesn't hesitate to send me scurrying off to Bricklink if he gets a part that's not ) my crazy building husband doesn't mind used sets - especially when the price point difference on some of the retired stuff can be hundreds (I'm looking at you, retired modulars) between new and used.
The thing that bugs him most regularly is that most people aren't as careful as he is in applying stickers (dual-wielded exacto knives, a metal straight edge, a jewelers magnifying light, and the hands of a surgeon are how HE does it, or, as he calls it, "right"), so I'm forever buying new sticker sets for his used purchases.