Best coffee on the road

so I have a job that sees me driving around the country so naturally I buy coffee in a bunch of different locations and I've noticed something quite curious BP and Z garages have the most consistent coffee as in it's not great but it's passible

Roadside coffee carts often have pretty good coffee also but what I've noticed is small local cafés tend to have dog shit burnt coffee or basically milky water

What am I doing wrong how can I tell if a local café is gonna serve me shit coffee or good coffee