KSing to induce rage/troll
I noticed a game today where a game was lost because a selfish mid kept KSing our ADC to the point he rage quit. ADC was getting shit on in lane mostly due to ganks and there was a very specific case where enemy support wasn't going anywhere but mid still KSed anyway. In the end, greedy mid lost game when he inevitably got caught by CC and focused down and then enemy team catches up.
The lesson appears to be do not be so greedy and take everything for yourself leaving your teammates with nothing and causing them to rage quit and throw otherwise winnable games.