I had a Groupon for a mani pedi and came in on a weekend. The staff were friendly and nice, but the manicure felt very informal and rushed. The manicurist kept asking me if the manicure felt alright, but the frequency was every 5 minutes, and I started to get the feeling that she had some complaints before.
When she asked if the nails looked alright, I noticed that the nail polish wasn't applied evenly, and it was messy around the cuticle. I asked her to clean them up, but even after 'fixing' it, they still looked worse than if I had done them myself.
I can't tell if they just don't want to honor Groupons anymore and did a poor job on purpose, or if they truly aren't familiar with how a good manicure should look. I can't imagine they retain many of the first time customers with services like that.