How do you feel when you have to force a smile, when dealing with a colleague for example? Are you able to spot the fake smiles of others?
It's not difficult to tell a fake smile from a genuine one, as people who are really happy smile with both their mouth AND their eyes. In a "Say Cheese" smile, their eyes don't change.
That said, I still prefer a fake smile to real indifference or rudeness, because I acknowledge that these people are making an effort to be polite or socially agreeable.