I happen to have a pushed image on the shelf next to me---TX at 1250 in Diafine---and I'm pondering whether I see anything in the image that really suggests the speed increase is an illusion (which of course it is). The contrast is pretty high and it has the gritty TX-in-Diafine look, but it doesn't give the impression of empty shadows. There are featureless black areas, of course, but they look fairly natural. The action is in the midtones, which really *are* faster when pushed. To my mind that's the definition of a situation well suited for non-special-effect pushing---you aren't trying to bring Zone Absolutely No Photons Got Here up to Zone II or whatever, you're trying to steepen the contrast curve so that the image is dominated by upper-midrange or midrange-midrange values instead of lower-midrange.