I know when I go to a romantic movie with someone we always end up more snuggly afterwards, it definitely affects your mood.
Actually I find from my romance site that most romances *do* start out head over heels and then they settle down into the more long term love that sustains. The head over heels hormone-rush stage is built into us as humans. So it's a lot of fun while it lasts, but it's important to realize it's a stage