Gosh, I'm so happy. Admittedly it was an amazing run - I found plate armor in the sewers and upgraded them into oblivion. Still, the feeling of happiness when I realized I arrived at the top was really nice.
Especially the learning curve of the game. Every time I try, I get a bit better. A few weeks ago I died at the Dwarfen City, and now I'm good enough to come back to the top. The experience of working on your skill and getting better is just really amazing, and I love how the game is hard, but doesnt feel punishing.