The Internet is full of frequently mentioned laws. I wrote about that in this article. For personal reference, I would like to coin some common patterns for me as well. This is one of them. You might want to refer to it when appropriate.
(Voit's) Law of Fanboy appearance: As an online discussion about any topic grows longer, the probability of an appearance of an fanboy who could not reached by arguments any more approaches 1.
For reference, please do use the hashtag: #LawOfFanboyAppearance
Source/Background
Oh boy, how many times did I observe that pattern?
In most cases, this is related to discussions around Apple. The term "Apple Fanboy" did even make its appearance on Wikipedia.
However, there are also other topics that do have high chances of attracting some sort of fanboys: Tesla, $youcurrentpoliticalcrisis, politics in general, and more.
When loyalty exceeds the acceptance of objective facts and counter arguments, it turns into some kind of cult or religion. While I consider myself as a member of some sort of cults myself, I don't ignore good arguments. Or at least I try to stay open minded and self-reflected. ;-)
Similar Ideas
People who came across Conway's law realize its similarity to this law in principle and wording.