One of the biggest, and most difficult, life lessons we can learn is about the responsibilities we have for other people's thoughts and feelings.
When we look at our own thoughts and feelings, the idea that we are responsible for our own seems pretty simple. We like the color blue because it reminds us of a peaceful sky. We are irritable today because we woke up on the wrong side of the bed. We have likes, dislikes, and a history that colors how we see our world. In other words, our thoughts and feelings are all about us. Our history, our mood, our personal goals, our outlook on life.
A shift seems to happen though when we start to look at the viewpoints of others. Somewhere along the way we somehow started to add ourselves to the equation. "People won't like me because I don't wear the right clothes." "My friend is acting distant today. I must have done something to upset him." "I need to go to dinner with my friends even though I don't feel well because they might be upset with me if I don't show."
Your friend may be acting distant today, but his feelings are about him. He may have just woken up in a bad mood. He may have a difficult exam or meeting to attend. We certainly understand all of these things when we look at us, but when we look at the feelings and thoughts of other people, we somehow think we are the cause of their problems, when in fact, we probably are not the cause at all. Just as our thoughts and feelings come from our own histories, dreams, and goals, so do the thoughts and feelings of other people. People's opinions are about them, not you. The responsibility for other people's thoughts and feelings is not ours, it is theirs. Our thoughts belong to us. The thoughts of others belong to them. We own our feelings and others own theirs.