What I think is most fascinating about poker is that it is an "every man's (or women's ) game. Anybody can win.
It's a true statement, but the chance for a complete fish to win the main event is of course very, very, very, very... ..small. (but there's still a theoretical chance).
I've not been playing for very long, but my favourite moment in poker was to watch Billy Pappas, poker amateur and 2014 November Niner, play the final table of the biggest poker tournament on the planet. He finished in fifth place, taking home over $2m in cash.
I think watching those final tables is what got me into the game. Seeing other's dreams come true, and allowing myself to dream big, is what fascinates me the most about poker.