Nah, it's (type + remember) speed that makes command lines frustrating. They're only fast if you use them constantly or write scripts. As soon as you have to look up an argument order or a command flag, you've lost all that efficiency.
You can also configure zsh to show you all the autocomplete options (files/directories, flags, command-specific arguments like git tags, etc.) and tab/arrow key through them visually: http://i47.tinypic.com/2qtwxnn.gif
(The gif is a little slow, but you can obviously move through them a fast as you can hit the keys)
In my experience, the slowdown is usually not remembering the command, but remembering, say, whether you want -f, -F, --force, --hard or some other option for this particular command.
Even common commands have this problem — for example, I don't copy files all that much, so when I do, I frequently forget that cp takes -R instead of -r.
It's program specific. The vast majority of linux distros come with GNU cp, which takes either. BSD's version of cp only takes -R, Mac's too I suppose since it's BSD-based.
The annoying ones on linux are chmod/chown, they take -R only.
EDIT: it's OS specific in the sense that these programs follow the OS's convention, I expect BusyBox cp, a lightweight Linux version of cp, has the same options as GNU cp
