Servility
Humility
Lack of backbone
thing is, after a while they can get cocky if they think you are humble. cocky and then snide comments can follow . i was discussing this with my workers last week and came to the conclusion that some customers could do with being frightened big time ,so that they would lose the cockiness . one idea might be to get a real ugly strangers face at their window,snarling "im gonna eat you ! "