Laugh on the other side of your face
Definition 1 of 1
Pro Tip 1/3Emotional Shift
The phrase often indicates a sudden change from happiness to disappointment or embarrassment. 
Winning the lotto, he bought a mansion, but laughed on the other side of his face when taxes came due.
Pro Tip 2/3Expectation vs. Reality
Used when someone's expectations are not met or turned out unfavorably, especially after being confident or boastful. 
He was sure he'd outperform everyone, but laughed on the other side of his face after seeing his results.
Pro Tip 3/3Conversational Tone
It's informal and best used in casual conversation rather than in formal settings like business or academic writing. 
She said her business would succeed without help, but she laughed on the other side of her face after the first year.