A quick guide to tipping
Tipping norms vary a lot depending on where you are and what kind of service you're getting. In the United States, 18–20% is standard at sit-down restaurants, while counter service or delivery usually runs 10–15%. In much of Latin America and Europe, service is often included in the bill already, and an additional tip — if given at all — tends to be smaller, more of a rounding-up gesture than a percentage calculation.
When in doubt, the safest read is: match the effort. A server who's been attentive over a two-hour dinner is in a different category from a barista who handed you a coffee over a counter.