To dream of happiness may reflect waking life situations where you feeling good about not having to worry about a problem anymore. Relief, comfort, or contentment with how a situation has turned out. Feeling secure or loved. Alternatively, happiness may reflect waking life situations where you feel really lucky about something good that has happened. Self-love.
Negatively, happiness in a dream may be a sign that you are desperately avoid facing the truth of a problem or are involved in addictive or excessive behaviors. Compensating, daydreaming, or willful blindness to avoid pain. A desire for wish fulfillment. It may also reflect a tendency to live with desire for things you can't really believe you can have. Wishful thinking. Happiness in a dream may be a sign that you are having problems facing the reality of situation. Alternatively, dreaming of being happy may reflect a tendency to be too comfortable with ideas or situations that are not good for you. Feelings about other people being happy to see your fail or your or enjoyment of experiencing other failing.
Happy endings in a dream may reflect positive outcomes that you currently aren't confident enough to believe in. Negatively, they may reflect satisfaction with keeping others down.
Example: A young boy dreamed of his parents being happy together and choosing to not get divorced. In waking life his parents were getting divorced and there was nothing that could be done to stop it. The dream most likely reflected the young boy's irrational or uniformed desire for his parents to get back together. Using hope or telling himself that his parents would get back together to help himself cope.