I'm pretty sure people around us can tell when we're being genuine and when we're faking it. That would account for my own experiences, when I'm forcing happiness for social reasons, when I'd rather just curl up and sleep for 15 or 16 hours straight. It occurs primarily when I'm out with friends (not that THAT'S happened recently ) and I bother myself by being kind of a goober: controlling the conversation, making inappropriate jokes, etc.

What you have, if I may, is what's called a false dichotomy - you're limiting yourself to only two alternatives, e.g. your "normal" state and your "happy" state. I would suggest there's a third alternative (well, there are infinite alternatives, but this is the ideal one) where you can be happy AND well-liked. How that happens and who that person is, I don't know, but from my own personal experience, I find that forcing it doesn't work at all. If you don't like who you become when "happy" you're fortunate enough to recognize that, and can attempt with some effort to change. It won't be easy, but would it be as rewarding if it were?

Much love, and good luck.