It has been reported by people within close circle of Imam that he rarely laughed and always smiled instead.
But once when Imam’s grandson, Ali, did not want to stay with the Imam and was in hurry to leave.
Imam said to him, "Come, Ali, give me a kiss and hug now and then go."
Ali said, "Today my kiss is bitter."
The Imam laughed and laughed a bit loudly and then said, "Take it well."
(Memoirs extracted from excerpts from the Life of Imam Khomeini)