buıʇʇǝs uoıʇɔǝɹıp ʞɔɐʇʇɐ
Or, people would take more time on their posts because there would be a rain of downvotes if they flamed, spammed etc.
In today's society, the worst posts (in terms of being constructive, but the 'best' in being funny) get the most likes. Just like the worst memes get the most popularity (Zoomer, Coomer, Boomer). Anything that goes against forum norms (such as spam) is 'different' and 'funny' therefore, usually gets people's 'like' button although usually isn't constructive.
The good thing about the 'best answers' feature, is that it rewards people for being helpful and constructive, which is pretty much all you need - If we were to adopt a similar feature throughout the forums, we could allow 'Questions' on every section, although that does come with other issues.