coal
Coal is known to be the opposite of gem on places like the far-right extremist forum Soyjak.party. Unlike gems, which are high quality and uncommon; and the average post, which is wholly average and neither coal nor gem; your average coalpost is a special combination of low quality and low effort. Coal does not serve any use for the community other than to occupy space that could have been a gem, making watchersby hopelessly lament what could have been. Coal is doubly detrimental because it floods gems off the board to be forever lost to continuous coal spam.