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
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.