The most egregious one, IMO, is the pay-for-attention 'feature' (bluetick replies end up at the top). _Everyone knows this is a terrible idea_. Dating sites have known it's problematic for 30 years (these days, those that still allow pay-for-attention tend to ration it, because otherwise peoples' swipe stacks or grids are full of, well, the sort of people who pay for attention on dating sites, which are probably not the sort of people you want to date). And yet they did it.