Is it possible for one to be wrong about one's own happiness? In other words, could one think (and feel that) they're happy without actually being so?

"I call no man happy until he is dead," said Solon, which is a bit longer than most of us are willing to wait. The point, though, is that we tend to use 'happiness' in two quite different senses. The first ('I feel happy now') is an immediate feeling of satisfaction and well-being. The second ('His years in Brazil were happy ones') is an over-all sense of achievement, purpose, peace, or again well-being. It is entirely possible for someone to have frequent sensations of happiness, over a long period of time, and yet in looking back think of themselves as broadly unhappy; likewise, a happy life doesn't necessarily require many moments of happiness in the first sense. I suppose it is also possible that the feeling of happiness even in the first sense could be mistaken, for example if 'artificially' induced by a drug. Similarly, the discomfort of indigestion might get mistaken for hunger. However, whereas indigestion and hunger are clearly physiological states that can be separately measured, whether...