Try using Office 2013. It's white and flat (even flatter in Win8 over Win7, you lose refrence to what the 'tools' part and the data part is. It is not inviting at all, unless you dig in to the options and try to put some slightly different colors/textures on it.
Getting off track, Apple design is simply not a monolithic, "zen" one-stroke entity. Apple design amalgamates understated hardware with loud, lickable user interfaces. To see my point, consider that Apple hardware is definitely NOT lickable, whereas software generally is. Historically this may be due to the dissonance between Forstall (software design) and Ive (engineering design).
(Feel free to shred me as I don't really know anything about Apple design.)
He didn't talk about gradients or drop shadows, he talked about textures. Wood grain is texture, the paper fibers in most book pages are texture, ... There is such a thing as too much texture, but there is also such a thing as not enough texture: when there's no texture, the work feels dead, like holding a single chord forever.
> Get rid of all texture, and you might end up with cold, sterile designs that scare users away.
I'm on board with the usability argument, but I don't think that removing gradients and drop shadows necessarily results in designs that "scare users away." If anything, I think that abandoning realism allows you more freedom in making a warm & inviting designs (e.g. some downright unnatural combinations of pastels that would look too busy with those touches of realism).