I have always maintained that if you treat others as you would like to be treated; your interactions with people you meet will go much smoother. I was told this by my Judo Sensei (My father) over 30 years ago and it has held me in good stead ever since.
Why not experiment today by approaching different people in different ways, making sure never to upset or offend anyone. Perhaps be overly friendly with one person and especially kind with another. People often mirror each other.
Often when met with an agitated and emotional staff member in school, I would approach them in exactly the same manner. Very quickly into the interaction I would completely change my attitude to one of serenity and calm. It is amazing how this hardly ever failed to illicit the exact same mood change in the person I was talking with.
Do unto others as you would like done unto you (sounds like Shakespeare or someone).