The new eBay vs. physics
The upper gradient on the new eBay’s gigantic ‘follow’ button (which, bizarrely, is rendered entirely as an image) looks like an inner shadow, and hence makes the entire button appears as if it’s pushed in — something you would expect from an active state, not pre-hit.
The meaning is then further confused by the drop shadow beneath the entire button, which gives the impression of the button floating above the surface — something that would be physically impossible if the button were depressed.
Please forgive the snark, but I feel like it’s important for huge companies like eBay to get this stuff right, especially with such a high-profile relaunch. This is, after all, 2014. It’s not about skeuomorphism vs. flat design; it’s about applying skeuomorphic elements (here, the gradients and the shadows) in a way that actually resembles the real world.
EBay’s button does something worse than highlight a disregard for good design: it highlights a disregard for physics.