Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
There are lots of evil things that proprietary software companies might do. Companies put their own profit above the rights and freedoms of their users, and to that end, much that can be done that subjugates users. Even as someone who avoids proprietary software, I still read many proprietary license agreements (mainly to see how bad they are). I've certainly become numb to the constant barrage of horrible restrictions they place on users. But, sometimes, proprietary licenses go so far that I'm taken aback by their gratuitous cruelty.
Apple's licenses are probably the easiest example of proprietary licensing terms that are well beyond reasonableness. Of course, Apple's licenses do the usual things like forbidding users from copying, modifying, sharing, and reverse engineering the software. But even worse, Apple also forbid users from running Apple software on any hardware that is not produced by Apple.