If I came around you house just to borrow some sugar I would of course take my helmet off. But helmet wearing scumbags intent on holding up a garage aren't going to remove their helmets when asked to, whereas someone sat on his bike waiting for the pump to be switched on probably isn't planning on holding up the garage.
Garages have rules and so do I. If they want to sell me petrol then they do it under my terms and one of those is that I keep my hat on if I want to
Von Grumble says it best
Anyway sugar's really bad for you but that's another thread