TF2 took a rather big part in my life. I've experienced many (if not all) of its intricate and well-thought-out mechanics, and as an advanced TF2 player with some experience in European leagues, I must say that I do not regret a single hour from my playtime (which is 95,940 minutes or ~67 full days). This is the only game that I know of that is updated relatively frequently and has a living community after almost 10 years since its release. Kudos to Valve.