For instance one of those things I've noticed is that most Discourse instances have those nag banners if you're not logged in begging you to log in – and that's one of the least objectionable things they do IMO. I discovered recently that Discourse also blacklists all but the most recent browsers (because Discourse is designed for the next ten years!) and serves up a plain text version on anything older… but not without a nag banner of its own admonishing you for not using a supported browser.
The infinite scrolling… ugh. I'm not a huge fan of XenForo, but as a successor to vBulletin it seems to be far more user friendly.
