How about the proprietary accessories? Right now, Apple has two of the worst AC adapters ever matched to portable computers (the MB/P Magsafes). The things are horribly rated and horribly unsafe, yet people have no choice to continue buying them, because Apple won't allow 3rd parties to manufacture equivalents. So you're stuck with an $80 adapter that almost always fails within the year by short circuiting and overheating enough to start a fire if unattended. Apple still hasn't redesigned them, so they're the only options out there if you want to run a Macbook/Pro.