"Like I said - that's how my life works." Wash has accepted this as his reality and is fully willing to just accept it as fact and move on. Blaming Gwen is a joke, but not everyone gets his sense of humor and that's not a good reaction. That's an Accidentally-Hit-A-Button reaction - he's had enough of those himself to be able to recognize them in the wild. "Okay," he says simply, and then, because it needs to be added, "For what it's worth, I was joking. I don't blame you for anything, and I don't plan on changing that." Unless she directly does something that requires blame, but he doesn't need to say that right now.