I've had this happen a fair few times over the past month.
Person (always been a man who has done it to me) driving or cycling along, either shouts something incomprehensible or makes a very odd loud noise as I'm walking on the pavement. It's just happened now.
I have no idea why. Should I be paranoid? Does this happen to anyone else? Is there any reason it happens other than the driver/cyclist being a twat?