Why does a free gift make you feel like you owe something back?
Nobody asked for the favor, yet the moment you take it, a little debt clicks on inside you.
The reciprocity norm is a built-in social rule: when someone gives us something, we feel pressure to give back. The pull works even for favors we never asked for and even toward people we do not particularly like. Taking without returning feels like an open debt, so we repay to make the uneasy feeling go away.
The phone-shop staff hands you a free coffee while you wait, and suddenly turning down the pricier case feels rude, so you buy it.
An unsolicited favor quietly tilts you toward saying yes to whatever the giver asks next.
Spot the free sample, trial, or small favor for what it is, and you can decide on the offer's real value instead of paying off a debt you never agreed to.
Free gift in, debt switch on - you pay it back to switch it off.
Learn the idea and practice English at the same time.