To me, the biggest middle finger Apple's flipped our way was the unceremonious removal of the Rosetta support from OS X Lion and onward. That move really shook this buyer's confidence in buying software. Now everytime I hear a rumor about Apple changing chipsets or even announcing a new OS, I don't get excited, I wonder how much of the stuff I bought is no longer going to work.
FWIW, my copy of Starcraft that I bought in 1998 still works great in Windows 95, 98, ME, 2000, XP, Vista, and 7. Haven't tried 8 yet.