I think it's always I good idea to try and keep the topic as relate-able to the game as you can. Even if you go off on a tangent while you play, a lot of people that are looking for some game play, for whichever game you are recording, they are more likely to want to hear about the game, rather than some story that doesn't even relate to the game lol. If something in the game reminds you of some personal funny story, that works too lol