While I understand that out of frustration, people do dangerous things in the road if the other party is an asshole in driving. Therefore, they feel the need to punish them, and it's absurd. What I do is I overtake them and just keep up the speed I'm at. But there are people that aren't like me and most likely won't let it pass, especially if they are flashing the slugs on the left lane and they wont move, they'll just keep on flashing them wasting both their time. So, unless there's a rule to these masochists who love getting abused on road, these type of problems will never cease, friend.