You are making a good decision wanting to make Applications for the Mac. Mac OS X Applications are better than Windows programs and Linux programs by far. To see Apple's awesome programming standards...
What...the...****...
Do you even know the slightest to what's involved? Apple has a document outlining the Mac OS X HIG, so does GNOME, so does KDE, so does Microsoft for Vista. Some languages even have such things, like Java. Without any guidelines, applications would be all over the place in terms of consistency and L&F. This doesn't mean that Apple/GNOME/KDE/Microsoft/Java et al are pointing a gun to the developer's head forcing them to follow. They're
guidelines, recommendations. Some deviate for good reason, others due to ignorance..either way..
Hey, Half-Life 2 doesn't run on Mac OS X. Does it make it a crappy application? Far from that. Same goes to many, many other applications. As for Linux..well, buddy, I suggest researching into what Mac OS X is based on. FreeBSD, but many applications still run, usually with little modification (see Fink, MacPorts, Xcode tools too and that it comes with gcc...)