Which became a self fulfilling prophecy in my experience: you buy a deal on a personal service like a hair salon, the staff assume you won't be a repeat customer so they give you terrible service which does not inspire you to return.
The stigma of using a coupon didn't bother me so much, most restaurant servers were always cool about redeeming them (and of course I always tipped on the pre-Groupon bill.) But I would sometimes get an (unintentional) negative vibe from higher ups, like great another money-losing customer that I'll never see again. That reaction is what discouraged me from using Groupon, if it just ends up generally being a bad proposition for businesses I'd rather just avoid the whole thing.
Oh man, this reminds me I still have a much of credit at Restaurant.com, which I stopped using a few years ago too...
But, yeah, online if there's a new customer discount or a periodic 20% off one item discount I'll use it to buy something I would probably have bought anyway. For most in-person things, I don't go out of the way to find/use coupons unless it's a very transactional thing like a museum admission.