The best question i've ever asked any doctor was when i half-jokingly asked an ID doctor who was telling me about his extensive travels if he had ever personally had any of the diseases he was talking about, and he said "Oh yes of course!" and proceeded to reel off about 10 bizarre tropical diseases that he'd experienced and how they all ranked in terms of unpleasantness.
I believe he said Leishmaniasis and a particularly painful bout of Dengue were tied as worst for him.