Meaning/Usage: Used to ask someone what's bothering them 习惯于问某人困扰他们的是什么

Explanation: When something is eating at you, it is consuming your thoughts, time, and energy. It makes you depressed and you suffer from it. This phrase is asking someone who looks depressed why they are not happy.

"You're in a bad mood today. What's eating you?"
"It seems like something is wrong. What's eating you?"
"What's eating you? You don't seem like yourself."

A. "You seem really upset. What's eating you?"
B. "My mom told me I cannot go out with you guys because we already have plans."
A. "That's ok. There's always next time."

Other Common Sentences

"What's bothering you?"
"What is troubling you?"