Aye, suppose when it's like that it would give you a start and yes, best to simply shrug your shoulders and leave it there.
Never let it eat at you, that sort of stuff ruins lives.
try to chill if you can ,I was following a slow bugger down a lane 40mph speed limit , this twat was doing 28 mph , so I was arse to arse with him. he kept braking every 10 yds lol , come to junction had to stop . a bloke got passenger side , said if you don't fook off from back of the car I will kill you . I said it don't bother me mate I dying from cancer , and if you don't speed up I will ram