RpNation

Usually played as a joke, for chunnibyo etc but its like that theory if a gun is introduced somewhere in the start of a film at some point someone's getting shot. But with no actual payoff or joke it's just annoying to me. Sorry none of this rhymes

This is especially bad in animes where combat is involved. Having only one eye fucks your depth perception, limits your field of view and would in general make you worse.