I love how I am still discovering things to this day, despite the game being out for almost three years now.
Today, for example, I only just discovered there is a hidden chest in Bleak Falls Barrow, in the antechamber leading to the Frostbite Spider lair. I also realised today that if you beat Hadvar (and I assume this works with Ralof, too) back to Riverwood, and initiate dialogue with Alvor (or Gerdur, I presume), you open up completely new dialogue options. I'd never before realised those two little things.
Aside from the hiddens gems you can find after several hundred hours of playthrough, there are other things that, for me, never get old.
- Slowly taking in your surrounding from the Throat of World. Spotting Whiterun far below, with the tundra spreading out into the horizon. Turning eastwards, and on a clear day, being able to spot Windhelm. The views in this game never cease to make me take a few minutes to just stop and stare.
- The chill when a Wispmother appears. I find those buggers creepy as heck, and they still make me shudder when they appear.
- How many little ruins, abandoned towers, outposts (etc) there are dotted around Skyrim. You'll be strolling through the untamed wilds and happen upon a collapsed and ruined structure or tower, and you'll wonder what it once was, and why was it abandoned. I always find my mind wandering and thinking up stories behind the little ruins, picturing them in their hayday before their decline.
- Something simple like hanging back in a city or village, and listening to the sounds of life and activity, watching the villagers go about their day, toiling in the fields, trading trinkets at the markets.
- Emerging from a nordic ruin, exhausted and exhilarated after a tough battle, and seeing the sun and the beauty of Skyrim. Hearing a distant dog bark and the unmistakable clang of a near by blacksmith, and realising that while you were doing battle with the powerful undead and exploring secrets no Nord has seen for centuries, life went on as ever, ignorant and unaware of your little adventure.