Bayazid
It is said about a Sufi mystic, Bayazid, that he was a tremendously happy man, almost ecstatic. Nobody had ever seen him unhappy, nobody had ever seen him sad, nobody had ever seen him doing anything like grumbling, like complaining. Whatsoever was – and he was happy. It was not always good, it was not always right for others. Sometimes there was no food, but he was happy. Sometimes for days he would live without food, but he was happy. Sometimes there were no clothes, but he was happy. Sometimes he had to sleep under the sky, but he was happy. His happiness remained undisturbed. It was unconditional.
-Osho, "Journey to the Heart, Talk #1"