Though there are many important reasons to practice dream interpretation, one of the most valuable rewards from this work is that it helps with waking day relationships. It is a rare circumstance that someone would have dreams that did not involve characters of some kind. Common characters include romantic partners (past, present and future), family members, strangers, co-workers, friends, peers, and celebrities.
Who you dream about is a function of who you think about, who you have interacted with in the past, and what waking day issues you are experiencing. The "who" of dreaming is very salient so when someone shows up in your dream, they are important to you, whether you realize it or not. It may not be the actual person that is important but something about him or her that is coming into awareness. The dream characters may represent a personality type (the issue is aggression), a situation (it's about family), a similar person (my sister shows up as my brother) or any number of issues (the bully at work shows up as the bully from grade school). Dream characters are filled with important information about our lives and since more than half of our dreams are about relationships, the meaning in relation to waking day lives is important. Dream characters have much to teach us if we are willing to listen.