As Ludacris says...What's your fantasy?
Having fantasies is normal and considered a healthy aspect of human sexuality. Fantasies can range in themes, settings, context, and content-- it's about what you want and since it's in a person's head, practically anything goes!
But what about the reasoning behind the content of our fantasies? We might want to know what's going on there. Luckily, a study by Dr. Birnbaum was able to dissect this for our inquiring minds. Dr. Birnbaum looked at the effects that security and anxiety in a relationship had on a person's fantasy. "Results indicated that the anxious relationship prime resulted in fantasies in which the self was seen as more aggressive toward and alienated from the partner (i.e., there was far less affection expressed) compared to the secure relationship prime" (Lehmiller, 2012). From the results, you might see that an anxious or insecure relationship can lead to less affectionate feelings and more distant types of fantasies. The researchers believed that "when we are feeling insecure, we may use our fantasies to create a psychological barrier between ourselves and our partners in order to protect our self-esteem" (Lehmiller, 2012).
Beyond content, when and where people find themselves fantasizing might be another question though. Have you ever found yourself zoning out into a fantasy at an incredibly inappropriate time? It happens, but no worries- only you know what was playing out in your head, right?