This location is by far the worst McDonald's I've gone to on the planet, and I've visited McD's on 4 continents. We've lived near this store well over a decade, and it is a convenient vice when time is short. Were it only a consistent vice as well. I've repeatedly talked to management. I've even talked through my connections to corporate Quality. The problem obviously is bad training and a franchisee who just doesn't care.
The problem is, it is rare for this store to get a drive through order correct. Order one sandwich, get another. Order one beverage, get another. Want black coffee? Get one with cream and sugar.
It's so bad that it's become a community joke when encountering bad service at a different establishment - "They must've hired that kid from McDonald's."
Maybe the sting of a public rebuke might help.