For me i found that i was only the bad guy if i took on that role. Someone screams and yells and those emotions in me would start to rise that i was responsible for doing something to make them feel better. Now what i work on is when someone is yelling and screaming about silly things i just say to myself that its their problem not mine. once i detach from their problems then i no longer feel like the bad guy no matter how much they want me to take that role on.
A wise counselor told me one time that me being to blame for what happens to my AS is about as realistic as me being able to cause an earthquake in china. So she taught me a mind game where when he starts going off i say to myself "i did not cause an earthquake in china." Its silly but it helped me to learn what was his problem, his bad mood, his consequence and what was mine. If it continues then i seperate myself -i also come up with great one line responses - "that sucks that happened to you," "wow it must be tough for you to feel that that way." then i removed myself from the line of fire - whether that be needing to take a trip to the grocery store or finding some chore around the house that takes all my focus. I also sing - its hard for AS to yell at me when I'm singing some tune and it blocks the noise from my head.
I remember one time that i had rented a carpet cleaner - when you rent it you have 24 hours to get the job done. His room needed to be done because the dog had peed in there and it smelled bad. but when i went in his room he was in a "mood" demanding that i leave his room - kept unplugging the carpet cleaner. I just repeatedly plugged it back it and kept singing my song no matter how many times he unplugged it or cussed at me. Since i didnt respond or ackowledge his mood and he got no reaction at all he eventually stopped and actually came to me later and apologized for being silly.
People are going to have bad days - we're going to act silly sometimes but when you get to the point that fixing his bad moods arent your responsibility then you'll be taking a huge step away from the bad guy role.