The undue emphasis on superficial happiness dissuades people with a healthy range of emotions. I inherited a melancholy disposition from my parents and tend to gloss over it socially. People don't know what to do with it, and that is their fault, as I can only be myself. This creates a strange tension: do they like me when life is good, or all the time? This tension is exacerbated further by being relatively young (28), single (meaning I should always be auditioning for a mate, or something), and, worst of all, existing within a culture (Christianity) that prizes the "has it all together" facade.
My response to all this is learning the games that make up surface-level social interactions and getting good at them. It is definitely faking it, but sometimes you stumble on someone who can talk and listen in equal amounts, at which point I know I can cut the bullshit.