I actually have two Disney pin collections. The first is a collection of mementos... Pins of parks gone to, tours gone on, and so forth. Those are my souvenirs (and if I can help it they tend towards involving the old school, black-and-white Mickey, because I love vintage animation art from the Twenties and Thirties).
My gratuitous pin collection is very specific: attractions and films based on Jules Verne, but only with Disney characters on them. So, for example, Mickey Mouse looking like Captain Nemo from 20,000 Leagues Under the Sea or Donald Duck riding Disneyland Paris' Space Mountain. That collection came about in a very natural way as I have actually been visiting all the Disney parks with Jules Verne references... I've been to Disneyland Paris and to Tokyo Disneysea, so my collection just started with pins I picked up when I went there. Unfortunately I never got the chance to ride WDW's 20,000 Leagues submarine ride.
As to why Jules Verne, he is my favourite author. I absolutely adore his work and many of the movies based on it, including Disney's 20,000 Leagues and In Search of the Castaways. I even run a blog on Victorian Science Fiction. In fact, it was 20,000 Leagues in combination with the Haunted Mansion that got me interested in Disney again as an adult, long after I stopped watching the movies and things as a teenager. I'm hoping to go back to France next year and to visit his actual home and grave in Amiens, as well as go to Disneyland Paris ^_^