I’ve tried not to block instances (or communities for that matter), because you never know what good communities may appear there at a later date. Instead I generally stick to viewing only my subscribed communities, while occasionally venturing out into Everything to see if there’s anything good I’ve missed.

I guess it’s like using Reddit front page vs using /r/all. I never liked /r/all, so doing it this way is much closer to my Reddit experience.

I guess the good thing is we can all tailor our experiences as we prefer :-)