Question

En muchos países, si el servicio en un restaurante es bueno los clientes le dejan una
al mesero

Answer 1

Answer:

Dejan una propina para el camarero.

Explanation:  

lo dejan para él / ella si hacen un buen trabajo al servirlos.

Answer 2

Answer:

the answere is "TIP" that means "propina" in spanish

Explanation:

When a customer receives a good deal at the restaurant, the waiter receives a tip for his services.

The tip is usually going from ten to fifteen percent of the total restaurant total bill.