Quoting his uncle, Fahham Mansuri reports: One day Imam al-Hadi (A.S) said, “I was brought reluctantly to the city of Samarra' (literally meaning one who sees it becomes happy). Now if they make me leave this city, I will do it reluctantly.” I said, “Why is that, my master?” The Imam said, “For its good climate, its sanitation and its little diseases.”
[Al-Amali by Shaykh al-Tusi: 281, H 545.]