In a study published in the Journal of Applied Social Psychology, they describe after-dinner mint can be used to dramatically increase a waiter’s tips.
The researchers divided the diners into four groups.
The first group of diners got no mints.
The second group had the waiters including mints with the check without mentioning it. The tips grew by 3% over the no mints group.
The third group had waiters bring out two mints per person by hand separate from the check and then say, “Would anybody like some mints before they leave?” This grew tips by 14%.
The final group had waiters bring out the check along with a few more mints. A short time later the waiter comes back with more mints, letting the customers know they had brought out some more mints just in case they wanted the extras. For this group, waiters saw an increase of 23% in tips.
Why the strategy in the final groups works so well? The reasons are reciprocity, personalization, and unexpectedness. These reasons are quite self-explanatory but you can look up more details in their paper.