I've been mulling the past couple days over what it is that I really like about Euphoria. I mean, I enjoy the theme, but there's been something else. Some reason that's caused me to nudge at friends that they should check it out when they have the time/energy.
It's the buy-in.
So often these days it feels like RP exists in a vacuum. Your pose is only acknowledged so long as it pertains to / aids / assists someone else and if a Staff NPC / metaplot event is present, you may as well forget about 'existing.' I know I've absolutely (on Arx this happens in almost every big scene I go to) spent entire scenes where 90% of my poses are to... myself. I had a scene on another game recently where I went to a public event, roughly 8 people. I posed in, someone acknowledged me! Gasp! And then a friend of theirs showed up and they never responded back to anything else (leaving a thread of conversation dangling, even).
But on Euphoria, there's buy-in. People will engage with you. People will pick up threads you didn't even expect and run with them. In an event scene, while trying to explain a concept, my character made a comment about 'You know how everyone sucks their stomach in...' and it was just sort of a flippant, silly way of explaining the idea. Another PC in the scene posed sucking their stomach in, considering it, deciding they were OK with their body, but experiencing that moment of self-doubt and oh gosh, that tickled me. It was a cute, funny pose and I felt flattered that my pose had been read.
So yeah, the engagement. I really, really dig the engagement and buy-in from the active players.