To clarify- I'm talking about the scenario where the road is flowing quite happily but someone decides to slow right down or stop to let someone in/out of a side road. Or they haven't observed what's happening around and cause an obstruction rather than helping!
Twice today it has caused chaos that I got caught up in.
First one, road bends to the right but there is a junction at the corner. A car stopped to let someone in/out, but then no one started driving again because a learner was confused as to whether they were supposed to go or not. And just as someone did start to move, a motorbike overtook so the stalemate started again.
The other one, someone stopped to let a van out of a side road, but by stopping they obstructed temp traffic lights. The van couldn't pull out because of the queue for the temp lights so even once the lights turned green no one could move.
Anyway, AIBU to think that while it's nice and polite to leave side roads clear so someone can pull out if traffic is heavy, or if you are turning in to indicate and slow down early giving the other drivers plenty of time to react, you do need to consider what else is going on around you! And if someone doesn't pull out into a gap you created, you shrug and carry on (carefully) because there could be a good reason why they haven't pulled out?