How much do you know your friend?

When one have quite some free time, will start thinking about many unimportant thing and started questioning from many expect.

As simple conversation made me wondering, for a friendship which is more than 20 yrs. How much can one person know you.

Personally, i felt each individual have 2 kind of behavior, 1 is how we behave while we are at work, another is while we were in a total relax stage chilling with friends. This 2 kind of behavior could be totally opposite. Human is a magical creature, god made everyone unique. Can't one just respect another as who they are? 

Is just tiny thing i felt offended being look down by an old friend. I am ok. Maybe just emo, so tiny little sentence being magnified into something big in my own head. Don't let yourself too free sometimes.