Exploding Dice

We played a game of Deadlands Sunday afternoon, The BFF, The Artist Extreeme, and me. This was the second time we played, the first was last month including The Rawk Star, so this was the first three-player game.
It went well, except for one little thing we forgot, which was actually a big thing. If you roll a six, you get to roll again, and add the six to whatever the next number is. And if the second number is another six, you get to keep going.
So for the first 3/4 of the game, we were all getting creamed in fights because some of the NPCs start at 7 even.
Pretty embarrassing to be looking for a rules clarification on something completely different, and realizing that you messed up a basic rule.
But it did serve to remind us why we play, not to win, or even get the rules right, but for the fun of being together.