Dreams are basicly your brain running a defrag program. All your thoughts, memories, desires, subconscious concerns, are organized into scenarios your brain can make sense of so as to gategorize and make sense of every thought. This is why a dream can mean everything or nothing. for instance if you had a gay dream, that could be the result of subconscious homosexual desires, or just a random memory involving the concept of "gay" being organized in your brain that night.

personally, I seem to have more vivid dreams the more physically hot I am, oddly enough. If I wrap myself up too tight and get hot enough to sweat while asleep, I'll have full-blown realistic nightmares. wheras if I'm relatively chilly at night I won't dream at all.

overall dreams are a funny thing, but I wouldn't worry about them too much. I've had dreams of being blasted on acid a few times myself (I've never tried acid).