OTOH, the businesses that offered the discounts were essentially commodities in the scheme. They created the value via their discounts that Groupon then sold to customers. Few cared about the businesses, as people were not buying the underlying service or product from those businesses.
Instead, the product was the discount itself, which they were buying from Groupon.
If you pay too little (not just get a discount or other small favor, but actually pay too little) then you are compromising your own experience and actually getting less value than the people paying full price.
So it's no surprise that such people are ultimately less satisfied. The primary benefit they are getting out of it is the chance to tell their friends how low of a price they got.