Hard to explain objectively; I think the things that turned me off to reddit back then (now it's more mainstream) were people's willingness to assume tons of knowledge of topics they didn't really know about, the general white, upper middle class male from the burbs tastes of things like r/music and other cultural subreddits. It felt like walking into a videogame fraternity and realizing I didn't belong there.

That's a highly subjective opinion...but it's how I felt. r/shitredditsays probably captures a bit of what made me uncomfortable.