Most mornings I stop at the drive-through Coffee People Park to get coffee and a scone or something. Everybody who works there is super chipper and peppy to the point of being ridiculous. I wonder if that's corporate policy. The boss sat them all down and said, "Look, people are grumpy in the morning and need their coffee. You're going to be their first human contact of the day. You need to be over-excited and they'll be happy even if they think you're loony and it's all an act. Happy customers come back and keep buying coffee."
I think it works.
And they have free coffee refills too on the same day! :P