Repeaters are your bread and butter.

I always try instill in my staff that we are in the business
of making repeaters. If we make a mistake, I don`t mind
as much if the error is in favor of the customers. For
example, I tell my staff that I would rather they put too
little ice in a coke than too much ice. There is nothing
more I hate than a place that gives me two ounces of
coke in a 12 ounce cup. We just want to focus on what
will make this one customer come again.