I work at maccas- and we aren't meant to sell fries that have been sat under the heaters for more than 7 minutes (10 minutes for hash browns).
After that, they go to soggy and gross. I'm not saying that some of us don't still sell them after that...
Oh and they are taken out of the freezer in the morning so they are often sat around defrosting for hours before they are cooked. This affects the way
they look and taste later.
If your fries are too brown, stale or limp, it's usually because of one of these, or the oil hasn't been changed- and that happens a lot
(either that or the fries are at least an hour old..... )
Seriously i could tell you some horror stories about the stuff that goes on in maccas and some of the other fast food restaurants.