Servers in restaurants frequently use the tactic of writing “thank you” on the backs of checks before delivering them to dining parties. Servers also frequently personalize their interaction with dining parties by signing their first name below the gratitude message. The effectiveness of these tactics in increasing tips was examined. In a field experiment conducted in an upscale restaurant in a large Northeastern city, a server wrote on the backs of the checks either nothing, “thank you,” or “thank you” plus her first name. The addition of “thank you” increased tip percentages, although personalization by adding her first name had no effect. It was concluded that the commonly employed low-cost tactic of expressing gratitude to customers by writing “thank you” on the check can produce a worthwhile return.