Some people are usually positive and cheerful. Some are dour and negative. Which type are you?
It can be hard sometimes to be objective about ourselves. We may think we are cheerful and positive, when we really are not. Or the opposite! Sometimes it helps to get an objective opinion from someone else.
Sometimes a short verse or text can inspire us enough to change our outlook. If you are a religious person, find some related text. Or try a poem from Rumi or some writings by Thoreau, etc.
Make a concerted effort to begin to cultivate a more positive attitude, leaving judgements and social labels at home. (Or in a drawer, if you’re at home!).

Many people can tell instantly if you have a negative attitude or if you feel superior. So treat other people as you would like to be treated! And give each person a chance.
In Neuro Linguistic Programming (NLP), a great tool to improve relationships and communication, we learn to respect everyone’s ”roadmap,” their view of the world. Everyone does the best they can, with the resources they have. We all have varying views and experiences.
Tell yourself when you wake up that you are going to have a great day and that you will make an effort to look at people favorably. Try writing a positive affirmation to this effect and put it up in a place you will see it first thing in the morning. If you know Emotional Freedom Technique (EFT) tapping, try that using this affirmation.
Intimacy is a totally different dimension. It is allowing the other to come into you, to see you as you see yourself. — Osho