What is wrong with shopping at Wal Mart?

I shop at Wal-Mart due to proximity. In the past I’ve avoided it. Now that I’m buying my own home products, foods and everyday living materials I found myself going to Wal-Mart. It’s cheap. What is actually wrong with Wal-Mart? I mean, if a bunch of small specialty stores offers something at a more expensive price, isn’t it more reasonable to buy the cheaper product? Also, is there a difference in how business is done between Wal-Mart and Target? Thanks!