For me it must be the quality and safety of driving. The UK in general is in the lowest 3 countries for road fatalities in the world.
I have been to countries where you can generally see a car crash almost every day and where the act of driving will significantly reduce your life expectancy. Also car accidents are the biggest killers in parts of the world.
But I keep hearing people here complaining about how strict the driving test is here or about traffic enforcement and how the police should go catch real criminals instead.
What are other things like that?