Late last night, I left my rMBP open, with no apps running, but a paused movie and nothing much else really up on the screen. It duly went to sleep as I have allowed it to do in the settings when nothing is happening. I go to wake it three or so hours later (man am I tired!) and the screen come back alive but the keyboard and the trackpag elicit no response and I cannot enter my password. So, I plugged in a USB mouse and keyboard and enter my password. It accept it and the screen just turns black (not off, but backlighting on black). Nothing happens, so I have to hard kill it with the power button and start again. Boot up is normal, I log in, and boom, lit-up black screen again! So I hard kill it for a second time. By now I am sweating bullets. It boots up quickly, I log in, something comes up about how the system was shut down unexpectedly and should it open the windows that were open before or not? I hit cancel, and everything works, and is just fine as far as I can tell. Now, I looked in the console for any dramatic error messages, but nothing stands out. HOWEVER, in the console I see that for those hours that I was asleep and the rMBP was also supposed to be asleep, it kept waking up every half hour to check something via WiFi (I did allow it to wake from sleep for WiFi). What if anything about this story stands out as something that I should be really worried about and fix or have a look taken at? I can post the relevant section of the console here if anyone is interested when I get home from work later.