My favorite Mastodon feature is the ability to subscribe to hashtags [1] which makes discovering people to connect with super easy and you don't feel like a victim to some magic algorithm.
Another thing I love about it is the small niche little community instances like this photographer [2] community. Themed instances make a huge difference in organizing your social media time - it feels less of a distraction and more of a purposeful exchange. I talk photos, close the browser tab and it feels like I've done what I set out to do, whereas whole purpose of Twitter is to steal your attention for the sake of ad revenue - so you start with a purpose and end up feeling like you've done free work for someone. Like one of those early internet gigs that made you to surf semi-random ads for few pennies.