Regarding trying to install apps: I have come across a few apps over the years that aren't available through synaptic, apt-get, or other package manager. You download them, unpack them in your home directory, and the minimal instructions that come with it say to compile it, run make, etc. Which won't work until you become root most of the time. Then the app won't work because, while the instructions tell you to compile with such-and-such flags, they don't tell you the actual flags to include in the command line, you have to track someone down who is familiar with Linux compilers because the you don't have time to go through 660 pages of documentation written for C programmers to find out which flags correspond to the written instructions for that app.

Or you have the case which happened to me not so long ago, where the install instructions tell you that you need to put a certain file with your Apache install, but they don't tell which of the numerous Apache folders in various places in Linux it is supposed to go. And no information online. Gahhh!!! I couldn't use the forums because I was on a very short deadline and couldn't wait.

Then there is the fun of trying to install ATI's drivers for their video cards. ATI's online instructions, still say "The display driver requires POSIX shared memory to be enabled on the system." And weirdly enough, apparently nobody in the Linux community knows any longer where to do this in current distributions. Or even if it is already enabled. I had a FireGL card that had to use the default Linux drivers because of this, because the proprietary drivers wouldn't work until the POSIX shared memory was enabled, and no one knew where to do this anymore.

Regarding Mac OSX, it is NOT true that you never have to use the command line. I have had to use it a number of times to install and run some apps. Once to install a USB wireless NIC, and a few times for security software (I did not realize that the firewall that comes with OSX was that weak in 10.4. Hopefully it has been beefed up in 10.6).