Alternate History Fiction

Do you ever ask yourself the question -What if I had not gone to that store then that situation may have turned out differently? Or what if I had arrived ten minutes earlier to work then I would not have been caught in this traffic accident, or if I had gone to this party I may have met the person of my dreams? I am not talking about second guessing a decision or about making a right or wrong decision but simply (or not so simply) how a subtle change in something you did may affect the outcome. I am referring to the "butterfly effect" where small changes in the initial condition of a dynamic system (from Wikipedia) can cause a larger variation in the long term.
The movie The Butterfly Effect (2004) is a good example of how the main character keeps trying to achieve a different outcome in his life by changing things in the past. The movie Frequency(2000) also touches on this same theme. If I had to choose between the two films I would go with Frequency. I like the alternate histories better in this movie and the combination of the detective work and the search for the "bad guy." While The Butterfly Effect deals with important human issues, I am not a big fan of Ashton Kutcher although he is easy on the eyes.
In the movie Frequency, the main characters, father and son, are communicating back and forth through time. The father had died many years before so the son had this wonderful opportunity to talk to his dad again and try to change the way things happened in the past but of course this brings on a whole new set of variables and changes not counted upon. They work together to change things until the right set of variables and conditions are achieved. The ending is a little on the corny side but still nice. I think the movie is worth the time to watch (and the Butterfly Effect is too!)