Some are as you say and others are just a thick person with a bit of power and loves it.
These are the types that try and take your sandwiches off you because they have butter in them.
Same with the re-fuelers I can understand with pre-booked CAT flights they come first but then again they tend to be earlier than your normal flying school flights.
But refuelers that do the morning rush then decide that GA can wait until they have had their breakfast. Then they go and dip the tanks etc. And only after they have done everything else they decide to bother there backside to pump some fuel.