I agree, most people cannot spot a fake smile, which is why we use them so often. How often to do we fake being happy and content and people don't catch it? How many times do we give hints that we are not okay, but people miss them as well. Environment is important, but if there is no warmth, no sense of community, I don't believe people will stick because we all want a sense of belonging and security.
Here is a link to test you ability to spot a fake smile . . . enjoy . . .