The thing about signs is that they are just simple things, occurrences that are nothing out of the ordinary until we make them extraordinary. It’s something that catches our attention because at that moment, we were either deep in thought or just being mindless, and that something breaks us out of our thoughts or thoughtlessness.
Either way, we decide whether to put meaning into it. We decide whether we interpret it or how we interpret it. And we decide how to act on that interpretation. It’s all in our heads. It’s just a human construct.