Logicians and Magicians

What is it about realizing you don't know someone anymore that makes you feel like you never did? Habits and expressions you thought only you noticed are lost, or worse, become someone else's. And how does all this happen so quickly? How can so much happen in a day? Things you hoped would always be there disappear. Nothing ever stays the same. Is it possible to get use to change? Is that even the problem? Logic fails.