pick at one’s nails

손톱을 뜯다

"I also broke some habits while I was on it," she said, "like picking at my nails and drinking coffee".

Assessing the Chances for the Next Wave of Obesity Drugs (Published 2009)

Potential new treatments for obesity work differ in their effectiveness, side effects and possibly price.

https://www.nytimes.com/2009/10/17/business/17obesitybar.html#:~:text=%22I%20also%20broke%20some%20habits%20while%20I%20was%20on%20it%2C%22%20she%20said%2C%20%22like%20picking%20at%20my%20nails%20and%20drinking%20coffee%22.%20