万事大吉, directly translated as 10,000 things prosperous is a chengyu with more utility in everyday life than most others. It basically means that everything is great, or 'A-OK' as my textbook likes to say.
For example, you could say:
"Just because you passed your interview don't think 万事大吉, the boss can still fire your ass."
For example, you could say:
"Just because you passed your interview don't think 万事大吉, the boss can still fire your ass."