When I changed some text from "He is" to "you are", I found myself wondering why the verb had to change? (I might have known this back in High School, but that's been a pretty long time ago.) Of course, we live in an age where you can find the answer to just about anything in ten seconds or less. Imagine you were growing up in 1978, or even 1988, and you wanted to know the answer to this question? First you would ask your parents, who might respond with that this is just how it is, and then you would ask a couple of your teachers until you got a definite answer.
One thing about me is that I will see things that might be rather trivial, but then I will get curious and want to know the answer.