The worst thing I have seen in a chain petstore was in petco in Jackson TN, they had a 1 1/2 foot redtail boa that was severely malnourished, every one of that snakes ribs were showing and its skin was loose. Made me very mad, I about asked an employee if they knew of it's condition but decided to leave since I knew I would not be able to keep my cool.

And on a funny note:
I had a lady (costumer, not employee) in petco tell me one time that she used to own a thirteen foot BP and that she always slept with it. I just smiled and nodded....

Again at petco, I got into an argument with one of the employees that I made friends with about weather or not they used to sell day geckos (they did, unles they used to have some other green lizard with reddish spots labeled "Day Gecko! ). I think she thought they were green anoles!