When you offer someone a practice, ask them to tell you if it did nothing, and mean it. Say out loud that plenty of these do not land.

What the research says

In a randomised experiment comparing mindful breathing, progressive muscle relaxation and loving kindness practice, mindful breathing produced the most decentering, which suggests these practices work along different routes rather than being interchangeable. That is a good reason to expect any one of them to suit some people and not others. The study looked at short inductions in a laboratory, not at what clients report back.

Strength of evidence: long taught, never tested. Widely used and long taught. No trial has established that it works.