Only I am in bad mood, and I must make me look nice.
即使我心情不好，也必須讓自己看起來很好。
Try to laugh out loud even though you are in bad mood.
即使你心情不好，也要盡情歡笑。
He was in bad mood, and showed no humor towards anyone.
他這幾天心情不好，對人沒好氣兒。
Treat yourself better. Eating what you like when you are in bad mood.
對我自己好一點，心情不好的時候，什么都別考慮，赴吃我自己愛吃的吧。