Marcus Aurelius, the “Last Good Emperor of Rome” stated that happiness resides within controlling only what is within our control and regarding the rest as a subject of nature. It is also worth noting that as a Stoic, he was socially inclined to act and respond to the actions of others in an admirable fashion.
When we look around at the people in our lives, we take them out of the scope of engagement and place them somewhere where they are kept responsible for their actions, they tend to act in an entirely different way, reasoning that explaining explicit behavior would prove to be more problematic than attempting to be themselves.
My opinion – First impressions are entirely out of our control and are a reflection on the person passing judgement, not the person being observed. Be okay with yourself.