Tri-Fector

If I were to randomly walk up to twenty five people, varying in ages, let's say from teen years on up, and asked them to name their top ten favorite movies of all time, I guarantee that a large percentage of them would include a trilogy movie in their list. The "Tri-fector" as I like to call it always seems to appeal to movie goers and bring in a surplus of money at the box office. They seem to captivate us and entice us. Fan clubs, conventions, websites, merchandise, and hours upon hours of watching the movie on end is a result of this. Trilogies including Star Wars (new and old), Indiana Jones, The Matrix, Lord of the Rings, Back to the Future, Jaws, Spider Man, Home Alone, Mighty Ducks,Jurassic Park, Austin Powers, and many more bring satisfaction to all. Some are satisfied with the works while others complain about specific substitutions or the end product. However, it seems as if when it comes down to it, the world and all ages love trilogies. Also, sometimes it is just best to leave a movie at three and not add on anymore (AGREE?) as well as changing the characters over time (AGREE?). Anyways I'm just curious about what your opinions are to this?