I love Yellowstone and the Tetons.
Memorable moments from several visits:
1. The night before we entered the park to embark on a 4 day back country trip, we camped out in one of those super popular campgrounds just outside the park. My buddy and I decided to just sleep out under the stars on sleeping pads and in bags. In the morning, he's nudging me whisper, "wake the F up!" I open my eyes and about 3 feet from the end of my sleeping bag is an adult buffalo. I was completely frozen in awe, fear... my own poop. He/she was completely harmless and just scouring the campground for food/garbage.
2. Driving through the park one time in a huge wind storm. Driving through the huge burn area of '88 (?) and I could literally hear standing dead trees snapping in half from the wind and falling. At the climax of the intensity trees were snapping and blowing across the road all around me. How I didn't get destroyed by one/several, I have no idea.
3. On that same trip, on the main road that runs north/south... a bunch of yahoo tourists stopped and created a line of traffic probably a mile long. After awhile I just got out of my Bronco and sat on the tailgate... then I heard a woman claim, "look!!! baby bear cubs!" and proceed to walk up the hillside, with a group of others, to follow and get closer to the cubs. lol.
That back country trip though was absolutely epic.