Because many people don't realize what they have until they lose it! They love the attention and think that you'll be there forever to provide it. With some people it's a game and they don't like to see "the one that got away" and will probably try to see if you'll pay attention to them again. This time they may even go out with you on a date or two, but DON'T! These types of people that know full well you like them and play with your head are not worth it! Happy to hear you have found someone else!