To be in a good mood; cheerful and pleasant. Describes a person's positive mood or disposition.
今日は機嫌がいいね。よく笑っている。
You're in a good mood today — you're laughing a lot.
午後になって彼の機嫌が良くなったので会話が弾んだ。
In the afternoon his mood improved, so the conversation became lively.
上司の機嫌がいいと仕事がスムーズに進む。
When the boss is in a good mood, work proceeds smoothly.