9) Beyond the game, what's involved in an ideal session?
Enjoying the company of the other players. Playing RPGs is a social experience -- and I don't play with people I don't like. That's not to say that I haven't had good experiences gaming with people that weren't my friends outside of the game, but if I actively dislike someone, I will not play with them.
There is a school of thought that holds that bad gaming is better than no gaming, but I disagree.
10) Largest in-game surprise you have experienced?
Hm. Nothing really springs to mind. I rarely play in mystery games, so there's seldomly a 'big reveal'. I do play in plotted games, but there the occurrences follow in a logical order.