If unfollowing everyone is too much effort (or too much potential drama from people assuming unfollow = no longer friends), then there is another way. Someone mentioned the Newsfeed Eradicator plugin the other day -- it replaces the FB News Feed with a thought-provoking quote...!
I've found that to be a really useful extension as well, stops you getting distracted by all the news feed posts when you just logged in to check an event or something.
https://addons.mozilla.org/en-GB/firefox/addon/news-feed-era...