I think some couriers do their fare share in stereotype creation. I used to spend alot of time on the road as a consultant (lol) and found they where the worst. They are obviously in a hurry, but I was always abused and once threatened by a courier.
Taxi's are a hard one, I find in australia the taxis can be very wild. They drive erratically to get that final fair, in NZ they are so different. I am always shocked when I am in NZ, the cabbies are so polite, and drive like professionals.
hrm.