There are basically two types of drivers: those who get worked up about people driving slowly in the left lane, and those who do it all the time and have no idea they’re upsetting everyone else.
In case you’re in the second group, some background: Every state has some sort of law that discourages people from traveling in the left lane on multi-lane roads and highways. It’s not that you’re never allowed in the left lane, just that you should only use it when necessary, for passing, then get back over.
That’s because even if you’re driving fast, there’s always someone going faster. If you promptly get back over after passing, that car will be able to pass you, allowing everyone on the road to get to their destinations as quickly as possible. If you don’t, it’ll inevitably lead to buildups of traffic and likely raise the chance of accidents.
via Vox
