Two psychologists have studied over 1,000 people's dreams (join in here), to examine how people assign meaning to them. Turns out we only bother to interpret the ones our waking selves agree with.
How so? Let's say you dream your partner saved you from a burning house in one dream and cheated on you in another. You'd probably shake the latter off as a silly dream, and look up "house, burning" in Dream Moods A-Z for the former. It's a self-serving bias — kind of like how Freud saw sex everywhere he looked for it.
So basically dreams can be self-fulfilling prophecies or an easy way to shirk off responsibility. But knowing that, now what? Should we crack open the dream journals, or write interpretations off to Never-never land?