My impression of HKers has always been they are very polite. No opinion on mainlanders although on a trip to China a few years back I thought it was a free for all with no rules, regs, or etiquite and kind of wild. Other thoughts are HKers are sort of elitist when comparing themselves to mainlanders but I have no significant experience to warrant exact judgement. Kind of how a Yankee would view a Southerner back in the states although it is not really true.