Influence

Predictable levers.

The main ones

Reciprocity, commitment and consistency, social proof, liking, authority and scarcity. Each is a shortcut that usually serves us and can be triggered deliberately.

Free samples work through reciprocity, not generosity.
Limited time offers exploit scarcity, real or manufactured.

Defending against them

Notice when a decision feels urgent, when you feel indebted, or when the only evidence is that others are doing it. Naming the lever weakens it.