I propose a new word “Synsaster” for when things go well. Opposite of Disaster. Synaster would be more correctly the opposite, but sounds too sinister.
1. an occurrence that causes great distress or destruction
2. a thing, project, etc., that fails or has been ruined
[C16 (originally in the sense: malevolent astral influence): from Italian disastro, from dis- (pejorative) + astro star, from Latin astrum, from Greek astron]