Sharing: It's one of the first things we're taught as children. One of the most basic social graces, sharing allows us to create new friendships, divvy up precious resources and expand our horizons. Too bad the board of directors of so many high-tech companies never figured this out. Companies like Sony, Apple and Iomega have been saddling us with proprietary memory solutions for years now. Here's our pick of 15 of the worst examples.