A smile is an invitation. So is a frown. So is a sad face, an angry face, or a serious face.
Body posture is also an invitation.
The next time you are in a large office or a social gathering, just be an observer. Once you've observed others and learned their invitations, you can look at yourself. Then admit that you invite what you get, and that you can learn and change. Be proud of how well you take care of yourself socially. Decide to start inviting the opposites of these negative adjectives.