It's interesting when I ask people how they are doing and what's new, they often reply "the usual". Yet what is the usual? There's no such thing in my mind as the usual. Just like matter is constantly changing and everybody has different biological reactions going on in their bodies, you physically can't have exactly the same day as you had before that, and before that. Every morning you wake up, having changed a slight bit; you may be thinking something different than the previous morning. We're not robots, we don't have the exact same actions programmed in our brain with no variety.
Why don't people really say what's on their mind? For certain, it's not the same thought as you had told me yesterday. We are constantly processing new information every minute of everyday; we just aren't aware of all of it. The sub-conscious mind is really still a complete mystery; we know it's there, we know a little bit about what kind of thoughts and actions it controls, yet we still can't know how it really works. The brain is estimated to produce around 70,000 thoughts per day. (http://www.brainhealthandpuzzles.com/fun_facts_about_the_brain.html)
While of course we won't be aware of that many, not even close, there's no way you can tell me there's nothing on your mind. Everything's on your mind; you just either aren't aware of it or don't want to talk about it. Ask someone about health; their health, their friends health, what they consider to be healthy, I know you will get a different answer from everyone. Even if you ask random persons on the street about something as mundane as the weather, they will all have a slightly different opinion. So of course you're thinking something different; of course you're not bored, our brains are too advanced to be bored. We just aren't utilizing them to the their full potential.
If the day ever comes when we will be able to completely understand the human mind, I don't even have adequate words to describe the effect that will have on the human race. It will change the whole world, and even the planets beyond us, far past our wildest dreams. It blows me away just to think of it.
So do me a favor, when I ask what's on your mind or how you're doing, tell me the truth; we all know you can't have nothing to say.