It all depends on what Tay-Tay means by shake it off, says Professor Kim Halford, a clinical psychologist from the University of Queensland.
If she means playing music and dancing, that can be a good strategy for dealing with negative vibes. "Music can be used mindfully to alter mood and shake things off," he says – though playing sad music can actually make things worse.
But if shaking it off means trying not to think about something, it's bad advice – like trying not to think about a pink elephant. You're better off trying to think stuff through, says Professor Halford. "Why did this person do what they did to you? Did you contribute? What do you want to do about it from here? Maybe talk it over with a trusted friend, to try to make sense."
A third possible meaning of shake it off is to get on with life and do other activities, like going for a walk or seeing friends – which is a good way to deal with feeling sad or hurt, he says.
If you still persistently feel really sad or angry for a couple of weeks after trying these strategies, it's time to seek assistance, he adds. "Get a referral to a clinical psychologist and see if some professional help can get you to shake it off."