This hole is terrifying. Not only is it a very difficult tee shot, but this green has always been the one that has scared me the most at Oakmont.
I've always felt that 15 created a perfect sense of emotion during your round after you walk off 14 green. First, you realize that you've only got about an hour left to play the golf course, and you don't want it to end. Second, it is a VERY difficult stretch of four holes coming in, and there is no room for error, so mentally you need to make sure you are all there until the finish. Third, 15-17 occupy the most secluded property on the course. It's the first time you really feel any isolation (there's a hill to the left of 15 fairway, and trees to the right on 15-17). If you look at the last picture (looking back up the fairway), you'll see that there's not much to see aside from the hole you are playing for the first time. It's much different than the rest of the course. For me, there are few holes that are able to generate so many different thoughts as you step onto the tee.
Plus, the way the tee blends into the 14th green is REALLY cool.