I've never liked Wal-Mart (I don't even shop there anymore) for a few reasons, but one of the biggest is unionization.

The issue of whether workers are happy with their job or not isn't as black & white as many people say it is. It's heavily dependent on store management rather than the upper echelons of management in Bentonville. The problem with unionization is that in areas that need workers to be unified and fight the abuse they get, they can't because corporate is supportive of measures to stop it.