Spiritually it is said that we are mirrors of each other. The good and bad things you see in other people are actually reflections of your own inner being. This can sometimes be unsettling to hear, and we might even feel defensive or deny that we could share traits with people that bother us in some way.
However, there is a more beautiful way of looking at it. If you experience the actions and verbalization of other people with detachment, you might be able to see more of yourself in them. This connection helps to generate compassion and understanding. We are all one, all wanting to be loved and accepted. Think of other people as your guides to a better you.
Many spiritual texts urge us to listen to those negative feelings that other people trigger in you because they show us precisely what we need to heal within ourselves. For example, if someone you know is always judging others and it makes you feel uncomfortable. It might be helpful to look at ways that you are also judgmental. If you acknowledge these same things in yourself, you then can start on the path to healing. The more conscious we are about our own behaviors, the more apt we are to accept and then give for healing these things about ourselves that we want to change. Without first noticing them, we cannot begin to heal the underlying issues.
It feels empowering to remember that as enlightened beings we have the choice to be anything we want to be. The first step to becoming who you want to be is first finding those things you want to change. Seeing them reflected in others is your first step toward success!