How Are You?

I don't why every time someone asks me a mundane question such as "How are you?" or "Do you like it?", I feel compelled to give them an honest reply.

I don't think that most people want to know how you are really doing when they ask "How are you?", and they most certainly do not care to know that "Well, I'm good, I guess. Kinda tired and I've only eaten a granola bar thus far today, so I'm kinda hungry too. Also, looking forward to a run later today, etc etc etc etc". But for some reason, my brain or mouth or soul will not allow me to just say "I'm fine".

Why though? Why do people ask perfunctory questions that they do not care to hear real answers to?