Type I: The Innocent Smiley - Innocent both in the sense of not meaning any harm and the sense of naivete. These folks are just nautrally sunny and can't understand why you're not. Often, they've had pretty sheltered and pleasant lives, but some are almost supernaturally optimistic in the face of trials that would drive most people to tears. They're generally nice people, but useless if you come to them with woes or problems; all they've got is, "Smile, Jesus loves you!"
Type II: The Smiley Enforcer - Whatever may be going badly in your life, however your personal chemistry is wired, that's no excuse not to rejoice 24-7, as far as these folks are concerned. People have smiled through worse circumstances than yours, so get smiling, darn it! God (like your high school gym teacher), apparently doesn't take kindly to "whiners." And never mind that Biblical personalities, Jesus included, showed a full range of human emotions, including the "bad" ones; "Jesus loves you, so you ought to smile- it's the least you could do."
Type III: The Smiley Snob - These really grind me, and I'm glad I've only met a few. Whereas the Smiley Enforcer wants you to fake joy even if you don't feel it, the Smiley Snob tells you that if you don't feel it, there's something spiritually wrong with you. It's not just wrong to show sadness or anger, or even to be sad or angry- sadness and anger are symptomatic of deeper wrong. If you weren't so sinful and unregenerate, you'd be full of joy and peace and your life would be cruising along just fine. You'd never feel the need to scream or cry. I'm not even sure where to start on how unscriptural this is, but I've met folks that buy it; "If you really loved Jesus, you'd always smile, without needing to fake it."
How does one interact constructively with such people if one is a natural pessimist, and how can we help the church to understand that people who aren't always happy aren't necessarily broken and may not want to be "fixed"?