Manual transmissions are actually a great example. Let's say your desired specs for a car are: rear-wheel drive, manual transmission, high performance, four-door sedan. Just that. At least in the U.S., this set of criteria narrows you down to a handful of BMWs, two GM products, and one Infiniti. That's it! (I'm probably forgetting something, and I'm deliberately excluding AWD cars, but I think my point still stands.)

You could compromise the "high performance" bit and get a Lexus IS250. You could compromise on having seating for four adults, and get a variety of coupes, etc, but if you want all those criteria together, your choices are limited.

Getting back to Windows vs. Apple, what's clearly irritating is that you can run Windows on absolutely anything. However, if you want Mac OS X, then suddenly all your options collapse, much as they might if you absolutely insisted on having a particular car brand. This is clearly one of the driving factors in the Hackintosh universe, so if you really and truly insist on a replaceable battery in a Mac laptop, then you've got an increasing incentive to buy non-Apple hardware.