It is true; you live inside your head. It is how you perceive the world is how you think the world functions. We all see things differently and this is good because it adds a great deal of variation to our existence.
We may ponder on a certain problem concerning another person but that other person may see the situation differently and may not even give it a second thought. What can irritate you may not irritate someone else and so on.
We live inside our mind and our world is painted and perceived by how our brain processes the images around us.
So don’t get yourself worried over things that perhaps other people would think little about. Instead, focus on being happy, well and treating other people respectfully and equally then the world you project can be the world you perceive.