It's something I've always struggled with. People say one thing, apparently they mean something else. Sometimes you should take someone at their word, other times they were "obviously joking" or it's "just a turn of phrase". Words having distinct and well defined meanings changes at seemingly random points in a conversation, and this is apparently the commonly agreed mode of communication among the majority of people.
I have accepted that this is just how it is, but I really would like to know *why*? It seems like an incomprehensible system. I've been trying to figure out why people do this, and the most common explanation I see is that it is to avoid being "rude", or hurting people's feelings.
But that doesn't make any sense. That would only work for people like me who can't tell what you mean.
If person A says X instead of Y to person B because they think Y will hurt their feelings, but it's assumed B knows A means Y when they say X, what changes? In this scenario saying X is like saying Y, so why an unnecessary layer of obfuscation?
Personally I've just started telling people they need to be straight with me, because I'll believe anything they tell me. The response to this is almost always a joke (I hope) that they will take advantage of it and trick me into all sorts of things. Which, if wanting to avoid being rude and hurting feelings is the goal of communication, feels like a very bad thing to say.