Psychologists say that there are two proven methods to get people to do you favors. For big favors, is better to use the foot-in-the-door tactic. For small ones, the technique is called door-in-the-face. Learn how you can put them to good—or evil!—use.
https://gizmodo.com/these-two-psychological-tricks-will-get-people-to-do-yo-513064707
