Curate, connect, and discover
This isn't about "which of your joints is objectively the worst", but rather "which of your joints is recently annoying you the most". Which could be a new problem, a worse problem, a problem that's unchanged but your circumstances have changed so now it's interfering with things more, etc.
This poll is also open to young and healthy people; if say you bruised your elbow yesterday, that counts as a joint that annoys you.