Some of them are not— at least for my MacBook. The caret symbol is for the control key (think caret -> control), and the slanted-looking T is the option/alt key (if you look at the graphic as though it's a path, you can see the path takes an alternate route).

Control doesn't have the caret, but it isn't used nearly as much as Cmd/Alt/Shift for shortcuts (mostly reserved for further modified versions of other shortcuts, and Unixy stuff). As it happens, I do have a caret of sorts on my Control key as it's remapped on to Caps Lock ;)

I had no trouble learning and coming to like how keyboard shortcuts are done on the Mac, and that's because I didn't consider my previous environment the authoritative way to use a computer just because I used it first. (See also users obsessed with maximising every window because that was the done thing on a 15" CRT)

first..you'd have to know to think about what the feature is named...

...on Windows...you can invoke any menu by pressing ALT and then the first letter of the menu or a designated letter on a menu option (or you can use the arrows)...all windows menus get this behavior by default, in addition to separate keyboard shortcuts that can also be defined in the application

...you can get to the menus on Macs through a rather inconvenient combo CTRL-F2 (CTRL-FN-F2 on Macbooks)...but you can only arrow through commands, there are no letter shortcuts in that case.

...I like OS X, but this is one area that Windows does much better (that and multiple monitors)...

Beyond the basics (cut/copy/paste/new/save/quit/...), there's a fair chance we don't know which sub-menu the function we're searching for resides in (and shouldn't have to care).

the fact that I (and apparently many others) learned about some OS X keyboard shortcuts through reading this thread indicates that there is still a problem with "discoverability"