I like Mastodon because it reminds me of all the independent BBS forums that were running around in the late 90's and early 2000's. Same software, independent communities.
I disliked Reddit from Day 1 because it absolutely destroyed these communities and centralized control. I still feel like a stupid zealot when I tell people "Yeah I'm into tech, the internet, forums, BUT NOT REDDIT".
I hope for people to relive the tight nit online community feel, Mastodon is on that path.