I was almost tempted to skip this, but in some ways I guess it's as much a part of the story as the story itself, so I left it in, despite not being all that personally fond of it.
I don't know, I guess I've never been all that happy about the whole "I'll tell you a true story now, and it'll be completely made-up bull" thing, even when it's with a hefty wink, like this. (And geez, anyone else from the newsgroup remember other people arguing that the book really was really originally written by Morgenstern, really? I swear I remember a few threads like that.)
Still, the whole framing device certainly makes the story more... memorable than it otherwise would be. And help to pave the way for some of the other quirks (uneven chapter lengths, "short" asides to the audience about the so-called original) that help give the story character. And it indirectly paved the way for the use of Peter Falk in the original... so all in all, it's not without its merits.
Still, since it is an introduction and not a proper part of the story itself, it's hard to figure out anything meaningful to say about it. Other than perhaps to note that of course the things that Goldman is pointing out about Morgenstern (ie, having the gall to call his story a classic right out of the gate) are actually true about himself instead, which is I suppose the point.
Or to wonder why Goldman, in his introduction, decided to make himself out to be a bit of an ass? Maybe he figured that since the introduction on the whole is obviously false, if he's painting himself like this it'll obviously be false as well, so the reader will be left with a much better impression of him? I dunno.