Brake testing as in full brake slam, is stupid, but everyone who uses it thinks he has a reason to.. I`ve lit the brakes (without slowing) a couple of times to make them aware they`re too close and they`re driving technique makes me feel unsafe.. you can see it in the mirrors(jerky etc).
Sam, not a really good thing to say "
Stop driving in the rear view mirror(s). Pay attention to the road ahead.". You really have to pay attention to everything, even at the gestures of the driver ahead/behind of you, some are on the phone(no handsfree, ..and that is prohibited here), some are picking their nose, some are talking to passengers and pause the conversation when they intend to make a move, or look in that direction(left/right turn, overtake etc).
You can "feel" if he`s distracted/relaxed by his movements/posture at the wheel related to the maneouvre they`re performing. Some girls/noobs are so tensed up, if you horn them while overtaking they`re imediatelly humping the sidewalk lol, or some when they turn the head, the hands&steering wheel follows.
Here we have to adapt, traffic is so heavy that a 2 lane street is driven 3 or 4 wide.. Sometimes 2 inches mirror to mirror between cars, and that is happening at 40-50~ mph.
I`m not a saint, once i used hard(er) braking on purpose to annoy someone.. didn`t happen in the city.. he brake tested me at 55mph then he started laughing hard with his friendz y0.. tards. They were in "something" around 50bhp, no brakes compared to my trashcan, big spoiler, broken fart-can exhaust, "radio" volume max, distorting, all in one package). Just me and them on my lane for miles(one lane in each direction). 1 mile or so, he had to obey my <10mph "speed limit".. for he had no way of overtaking if i didn`t let them, the other way/lane had some incoming traffic (trucks and such) and whenever they attempted an overtake, i`d be 5 car lenghts ahead of them. I got really bored tho and floored it when he gave up "struggling". Meh, everyone has to be a tard sometimes.. I know i was, but it felt good..
Romania: Some truckers. "normal" overtaking style 1, 2, 3, here - laugh.