The Blessed One said, "And how, Nandiya, does a disciple of the noble ones live heedlessly? There is the case where a disciple of the noble ones is endowed with verified confidence in the Awakened One: ‘Indeed, the Blessed One is worthy and rightly self-awakened, consummate in knowledge & conduct, well-gone, an expert with regard to the world, unexcelled as a trainer for those people fit to be tamed, the Teacher of divine & human beings, awakened, blessed.’ Content with that verified confidence in the Awakened One, he does not exert himself further in solitude by day or seclusion by night. For him, living thus heedlessly, there is no joy. There being no joy, there is no rapture. There being no rapture, there is no serenity. There being no serenity, he dwells in pain. When pained, the mind does not become centered. When the mind is uncentered, phenomena do not become manifest. When phenomena are not manifest, he is reckoned simply as one who dwells heedlessly.
Don’t know as I am not an Arahant.
But Buddha said that Nibbana is the highest happiness.
So I took that on the face value.
If someone say that s/he is 100% happy, I take them to be Arahants.
It appears in this survey at least 3 people said they are 100% happy.
I am not sure what they mean by that.