It is not uncommon to go into a place of business and see someone with headphones in their ears. Especially if they work in an office environment. If not headphones at work...maybe they have a radio on or it is playing through their computer.
Smiling is an important thing to be able to do. I mean who doesn't want a smiling face greeting you. It doesn't matter if it is at work, school or wherever a smile is one of the most important things to put on in the morning.