Again, nitpicking here, but since I'm not the first one, I'll go ahead.
There is a difference between entering a password twice when registering, and entering password when logging in. If you mistype your password when registering, you wouldn't know it, since it's hidden. Subsequently, you wouldn't be able to log in, since the system recorded a mistyped password. Therefore, they have to ask you twice, to make sure you didn't mistype. When you log into Windows, you don't have to type it twice. If you mistype, it will just ask you again (and again, and again) until you get it right (or exceed the max number of attempts). This should be the case with wireless network settings as well. There is absolutely no valid reason for having to type it twice.
Here's another example where Windows just gives you too much information (unnecessarily), and Mac just does its thing. When you plug in a USB memory device, Mac mounts it on your desktop. Icon shows up and you're ready to use. Windows will actually give you a prompt (something like 'USB storage device found...', etc). It will do the same thing (map a drive letter to it), and you will be able to use it; it just pops up this unnecessary message. I know at least three (elderly) people that always get confused by this 'error' message they're getting on their screen; they cannot connect the two events (sticking in the USB memory, message popping up 5 seconds later). This is obviously a minute nuance, but it shows the essence of these subtle differences between a system that reports dutifully on anything it does, and a system that quietly does its thing and steps out of the way.
Again, bigger point here is, all these arbitrary, unintuitive and illogical inconsistencies continue to drive home the same point of usability of a system.