Our cafeteria at work is union. There is something about getting a decent wage which seems to inspire them. The food is really good (the best cafeteria of the 4 I've had at work) and they're quite pleasant.

If you see the same people every day, it can become natural to treat them as coworkers rather than staff.

Treating people well starts with paying them well, but has to continue with respecting them.

They're dealing with the general public, they're nowhere near well compensated enough to put up with that.