Mind & EverydayMental model
Forbid something and it suddenly becomes attractive.
Jack Brehm described reactance in 1966: when your freedom feels threatened, you want exactly what is being restricted more than before. Warnings, bans and "you must" trigger it; the message then gets rejected however good it is. The thinking tool: to persuade, leave a choice. Adding "but you are free to decide" to a request measurably raises compliance in studies.
Useful: Tell your teenager what you'd like, and then that it's their decision.
Source: en.wikipedia.org