They're the same shortcuts. If he doesn't know the Excel and Word shortcuts, he doesn't know the system wide ones either because they're the same ones. If he doesn't know basic shortcuts, he knows little about the OS. It's basic logic. Further, the shortcuts themselves are all over the menus in every app and in the OS itself.
Syn, you're grasping for straws on this argument. The guy obviously made an incorrect statement and I called him out on it to demonstrate an example of how people think they know about Mac, shoot it down and end up not knowing much at all.
Hipster Duck unequivocally affirms that you can't use shortcuts in Excel and Word. These apps use the same system wide Mac shortcuts. If he'd had any experience with Mac, he'd know those shortcuts and would apply them to the MS programs.
P for Print, N for New document, O for Open, S for Save, F for Find, A for Select All... and on and on. They're the same in the Mac and Windows versions of Word and Excel. If one doesn't know that, they haven't used a Mac enough to figure out that very basic function of the ⌘ key and they certainly haven't earned the right to criticize something they know so little about.