I have partecipated to a challenge that had a very nice idea, that was to delegate for a week the amount of 50k of SP to the person that will get more votes that will bring the post on the top of the pile.
The initiative was AMAZING and you can see the post here.
The blogger/writer was @thecryptodrive that had this brilliant idea of delegate SP for this challenge once the post pays out and GUESS WHAT??? I won it.
Then honestly the prize was quite high and people (me included) were starting fighting to become first.
In this way the nice idea become a nightmare and people becomes very greedy and writing bad comments.