Savage Worlds, but probably not for the reason you'd think.
I've owned three different editions of Savage Worlds --- Explorer's, Deluxe, and Adventure.
From 2013 until 2021, it was the only system I GM'd. I GM'd 4 different settings/campaigns, 2 of which lasted at least 14 months.
I loved Savage Worlds. Still do in many ways. It's the first system that I ever truly made "my own." Savage Worlds was my system. The core of the rules and the freeform, skill-based character creation was a dream.
But by the end, my heart was broken, because somewhere along the way I fell out of love with Savage Worlds combat.
I don't know if something just got lost in translation moving from Deluxe edition to Adventure edition, or what, but where I'd never minded or cared about the swinginess of combat, suddenly it began to feel . . . not forced, exactly, but random. It no longer felt like player skill and tactics were making the difference, so much as just players waiting around for the dice to explode. My players knew all the min-maxing tricks, so it was getting harder to challenge them in combat without "over-tuning" the encounters.
And so at the start of this year, I began to feel my prior ardor just slipping away.
Early in 2020 we tried Edge of the Empire, and we really liked it. It was fun, and new, and fresh again, and the narrative dice really added something new, but when Covid hit, it threw everything into a loop. I ended up having to reorganize our gaming group.
Earlier this year, I convinced the group to try out Ironsworn, and it's gone so much better than I could have imagined or hoped. Our group is stoked to play Ironsworn now.
It's just been time to try new stuff. For sure Ironsworn will continue. We're going to play some Tiny D6 / Tiny Frontiers Sci-Fi. We're definitely going to jump back into FFG Star Wars / Genesys at some point. The combat model in Spellbound Kingdoms sounds different and intriguing enough that I'm definitely going to give it a shot, even though I think the setting is kind of whack. My kids love the Dragon Prince cartoon, and I've been intrigued by the Cortex+ system for a long time. And if Swords of the Serpentine ever makes it out of "beta preview", I'll probably buy a copy of that too.
Savage Worlds will always hold a fond place in my heart, but at the end, in 2021, it was just time to move on and try something new.