The Flying Spaghetti Monster completely lacks any qualities that would entitle it to legitimately be someone's focus of worship. It's too easily defined, it has very obvious limitations, and that just doesn't work.

That is the main thing wrong with all forms of idolatry. They're extremely limited, both in their characteristics, in their concept, and in their definition. They're just bigger versions of other limited things that we're already quite familiar with. And that means...no big deal!

For instance: it clearly looks like spaghetti, and it flies, and it's a "monster", therefore it's measureably large and/or monstrous, and all that simply doesn't work. God either...

1. doesn't look like anything

or

2. looks like everything

and as a result

3. is immeasurable, neither small nor large but simply infinite in both directions, indefinable, has either all or none of the various   characteristics we can come up with in a definition, and cannot be seen, unless seen implicitly in everything.

And I think I'll just leave it at that, rather than elaborating further. ;-) It wouldn't do any good anyway. It would probably be rather like trying to teach a pig how to do calculus.