No - pieces of terrain is the things you generate and place on the field. In your pizza example, "pieces of terrain" would be pizza topping. And it got FAQd for a reason. For a similar scenario, check out the "What is a succesful cast" discussion going on, primarily because of Dark Acolyte. Dark acolyte told you to apply it after a successful cast (adding to the cast value), but got FAQ'd to be BEFORE dispels. This technically means "succesful casts" happen before dispels, which is obviously not true - It got FAQ'd because it was obviously poorly written. So it takes precedence over another rule being equally clear in "All terrain is threated as difficult"?
I mean, that's the debate. To answer the question, yes: I think that it does overrule 'all terrain' (even if you want to call it terrain) because of that 'does not affect the game' bit. *shrug* Up to the gamers.