Yami believed he understood what Serena was talking about. "Sometimes. Honestly its because games and puzzles have some similar pieces that can make them easy to solve and complete. Though Duel Monsters is like that there are infinite combinations and strategies. Is that what you mean?" 

Seto stopped when Mokuba began to stumble and sway. He swayed his brother toward him and caught him, picking him up and carrying him. "I'm sorry Mokuba. I should have known better." There was more he wanted to say. But it all got caught in his throat.