I think that's probably an indication that the whole "It's not a replacement for the Start Menu, it is the Start Menu" school of thought is a bit flawed.

They've removed all visual cues that let you know what things do. You'd have no way of knowing that clicking the bottom left takes you to metro if someone or something doesn't tell you. If you click on the bottom right corner, you minimize all windows -- There's a visual cue for this in windows 7. The button still exists, but they've removed this visual cue in Windows 8, and I have no idea why. I'm really baffled by it.