Oh, that'll encourage them to be sweet FOR SURE! Yeah, we're really worried about them being SERVILE to us..!
Gosh, Jean-Claude, the way you keep shop needs improvement --couldn't you stop being so SERVILE, and scoff and snort a bit more?
Maybe roll your eyes skyward? Shake your head a bit and sigh?
THEN the traveler's checks will REALLY just fly out of my wallet!
The point this statement illustrates is, the froggies themselves don't know how to serve their customers without feeling servile. It is a common trait of narcissistic people with crappy self esteem.