In movies, definitely romance happens too fast. On TV shows, though, they are almost always dragged out way too long to the point where I just stop caring. Mulder & Scully are a good example of that, as are Josh & Donna on West Wing. Absolutely there should be a slow burn with good character development but many writers are really bad at knowing when enough's enough. If you want me to believe that two characters can't live without each other, then don't show me 7+ seasons of them doing exactly that...