A common superstition in Japanese culture: stupid people are immune to colds. When invoked, may lead to a Delayed Reaction of "did you just call me an idiot?" This has an equivalent in French, where Coryza is commonly known as "Rhume de cerveau" (brain cold), which people without a brain obviously can't catch. The English phrase "too slow to catch a cold" may or may not be related. If there is any Real Life explanation, it may be that idiots are too stupid to realize they even have a cold, then ignore it until it goes away. Examples of Idiots Cannot Catch Colds include: