This idea comes from a concept of happiness that is itself delusional. That delusion goes something like this: Happiness depends on getting all of my circumstances just so. When all the various aspects of my life—finances, career, relationships, property, body shape, etc.—attain some imagined optimum, then I’ll be happy.
If that’s how one imagines happiness, then yes, one had better be able to suspend reality, because that’s just not the way it works. Circumstances are in constant flux. You can’t go staking your well-being on them.
The word “happiness” has become so tainted by that particular delusion (relentlessly reinforced by our consumer culture, by the way) that it’s almost impossible to imagine a different kind of happiness.
I find the word “equanimity” to be more useful, precisely because it points to a well-being that is independent of all that flux. It just calmly accepts one set of circumstances as well as another, without being overwhelmed by this one and thrilled with this other one. It’s not an emotion-based happiness, because the emotions are also just part of the flux of circumstances. Equanimity operates at a higher level than the emotions, so that one can accept both grief and bliss with equanimity. Neither perturbs one’s fundamental well-being. “Yesterday I was sad, and that was fine. Today, I’m giddy and playful, and that’s fine too”.
There’s immense freedom in that kind of equanimity, and it’s that freedom that makes it a happy state.