i specified cashiers because they typically take the brunt and will easily be able to determine who is the worst, those selected however will have the opportunity to decide how they die, essentially a morbid make-a-wish foundation
my personal idea to solve this is to allow retail workers, specifically cashiers, to legally murder a single customer they dont like once a year, this will accomplish three things:
1. weeds out the arrogant and stupid people from the gene pool preventing the worst of humanity from procreating and breeding stupidity.
2. forces people to stop and think before they act as their life may be on the line for it.
3. obviously reduces the population significantly due to the number of cashiers on the planet.