We can start with the people who have to come to a full stop to make a left turn.
We have a road near here that is so congested that they put up lights with turn arounds for people to use who need to turn left. Because, if someone wants to make a left turn otherwise, they stop traffic and no one coming head on will ever stop to let someone turn across traffic. But, the idea of going down further and doing a Uturn to make their left turn into a right turn just blows the minds of most of these idiots. And, when traffic stops because someone wants to make a left, it's not uncommon to hear gunfire. This is a very serious road.