The Cortex rules say (and I'm paraphrasing from memory) that critical failures happen when all the dice are 1's.
Is this all the dice, or just the stat and skill? If I have an asset that adds a die, does that have to be a 1 for a critical failure? What if I throw in a plot point? I'd say a strict interpretation of the rules is that it is all the dice, but that seems like it's going to really decrease the critical failure rate.