The flip-back-and-forth example given in the post: http://shkspr.mobi/blog/wp-content/uploads/2013/01/Design-Di...
Notice how the edges are now fuzzy? On the buttons, on the edge just below the map, on the cog. That sticks out to me personally on this monitor here, and I tend to find differences like becoming even more noticeable when looking at the phone with it's hi-res "Retina" display.
They may not be crazy; they just notice different things. :)