Out of all the games I played, I think I put the most hours into Phantasy Star Online Ver. 2 for the Dreamcast. In my freshman at least 6+ hours a day during the school week and 12+ hours on weekends, days off, "days I was sick", 2 weeks with Salmonella poisoning, and the 2 hours I would wake up before school to watch Sailor Moon at 5:30 in the morning. During my school hours I spent so much time reading and memorizing the players guide I became a walking talking players guide, I had every map variation memorized. If I popped into an area and found a Monomate in Box A, I had the rest of the area on lock down.
I mastered enemy attack animation's to the point where I could time close range combat with Mechgun's to the last attack cycle of them and flick the thumb stick to avoid an enemy attack at the exact point in their animation where they would make contact. Too bad I started playing the game when they stopped supporting the DC online