My cursory experience with McD's drive-thru's ( several times a month, I guess ) gives me a very postive impression of the workers, and the system under which they operate. For example, I've noticed that the cashiers do double duty taking orders, and that's a feat right there. 'Course, these tend to be the old guys! Overall, though, very polite, efficient, and accommodating. Very possibly, they consider themselves underpaid and resent their situation, but they are sure doing their job.
BTW, just this past week, I had a morning commitment and took the risk of nipping thru a McD's on the way to get a coffee and Bacon-Egg-and-Cheese-Biscuit. There was a line, but I swear I never stopped rolling! I was afraid I was holding things up by fumbling for change! I went right around and right back on the road ... no more delay than a long traffic light. I swear.
In my area “fast food” has become anything but; few American workers (including managers) and everything moves very slowly. It is better along highways, but in the ‘hood it moves at the pace of the ‘hood...