Seeing that the Brits and Aussies started this slang business to discuss various imperfections in authority figures without said figures figuring out what was being said about them (may be another “urban myth”), it would seem that the intents of these kinds of “insults” are good natured, versus those that we throw at each other here in the States. Us Yanks like to pride ourselves on assuring the recipient is fully aware that they HAVE BEEN INSULTED! Also, since we’re always doing things in a hurry we don’t have time to be subtle and we can’t wait for the other person to “think about it”. It’s a very efficient usages of time to 1) honk horn; 2) receive the standard “F*** you!”; 3) reply with “A$$hole!”; 4) continue our journey of taking the kids to soccer practice.