I don’t know where you live, but here in Oklahoma, the worst fast food places are those staffed by Mexicans (most likely illegals, as they cannot or refuse to speak understandable English) and the local “Amish folk” (they also refuse to speak understandable English!). I am referring to McDs here, and these are some of the worst I have been at ever, in terms of service, food, cleanliness, etc. We don’t patronize these anymore... (Drive through times of 8-10 minutes on early Sunday morning...)
Sadly, one of our past favorite Chinese places started going downhill when they hired Mexican cooks (no less!) and the prices went up! Service was still good, but the food changed quite a bit...
Me and my brother were in a Deluxe Suites for a while in Dallas and there was a local Jack N da Box. When the main guy was there it was always perfect and fine, when he was off the place was a craphole.
Seriously. They had this one Marine-type guy (he may really be one too). If I saw him there I knew I’d get a great burger and good service. If he wasn’t there, I was lucky to get anything remotely like what I ordered.
First ring Philly burb. The McD's I normally frequent are inside Philly limits. Spanish speaking crews here win hands down for both efficiency and curtesy.
There was a review of a Mexican restaurant around here where the reviewer complained that they’d been told the place served “authentic” Mexican food but that the floors were dirty and the plates were greasy.
I replied, “well, you SAID you wanted authentic Mexican food. What are you complaining about?”