I used to work at a Subway, and although the tuna was generally pretty good, the avocado always turned brown quickly. I'm sure it was still okay to eat (it goes brown in just a few minutes), but we were told to keep turning it over with a spoon so that the lower, greener avocado was on top and looked fresher. It felt very untruthful.
I know a lot of take-away sushi and sashimi places that will have raw fish standing out on display all day, and as a result I never buy any unless it's first thing in the morning. It's not worth it to eat raw fish that's been sitting exposed at room temperature all day.
That said, it really does depend on the individual place. I've worked in places that are absolutely amazing when it comes to proper food quality and hygiene. I doubt you can really apply any blanket statement about the shortcuts individual workers take, and how managers run things. And the same can be said of the food you buy at the supermarket, or anywhere really. Hundreds of people have had access to it between the farm and your mouth. Chances are, at least a few took shortcuts here and there, and some of these may have affected the food to some extent. It's a fact of life, isn't it?