How, exactly, did Walter climb the Himalayas with only basic equipment and no training?
It's not like he was aiming for the top (which would definitely require more advanced equipment), and perhaps he and the guides use a more navigable route. Remember, he was looking for Sean, and Sean was looking for a snow leopard's habitat.
So, did he ever wake up from that mental trip on Greenland, when he pictured Cheryl, or was it All Just a Dream? His following daydreamings feel way more organic, and the coincidences and call-backs pile up from then on.
What do you mean mental trip? When he pictured Cheryl singing Space Oddity? The dream eventually faded back to reality with him actually boarding the helicopter. Then he jumps into shark-filled, stormy waters (well, it was about to get stormy) and is attacked by a shark. After being rescued moments before a shark snaps where he was a second ago, he touches one of his rescuer's faces and confirms that it was all real and that he almost got killed by a shark. By the end, with all the adventure he'd been on, Walter's daydreams have ceased to appear to the viewers.
Correct me if I'm wrong, but I believe the last daydream we see is when Walter pictures himself as a guest star on the Conan (O'Brien) talk show airing on a tv inside a cab. He himself ends it by getting out of the cab.
Some of his dreams take over reality, some of them just sort of intersperse themselves in his reality. Seeing Cheryl is one of the latter, where he never actually left the 'real' world, he just pictured her there. Whereas his fight with evil Ben was just pure daydreaming fantasy.
Why didn't Sean O'Connell recognize Walter Mitty if, as revealed in the end, he was stalking him and taking candid photos of him only a short while ago? Even with the beard, Walter's looks haven't changed that much.
