Mel Robbins
Let Them means allowing others their reactions; Let Me means deciding how to respond.
Attempting to manage the actions and opinions of others only amplifies your own stress and anxiety.
In Robbins's framework, when someone disappoints you or makes a choice you disagree with, mentally saying "Let them" helps interrupt the urge to react and leaves room to choose your own response.
Applying the second step allows you to take responsibility for the things you can actually control, like setting boundaries and managing your own emotions.