My bad ass self comes out in the same way that a kick-me dog thinks it can take on a pit bull...reckless and stupid.
I volunteered at a mixed ward (murder and mental illness) at Napa State for six months and got to know the guys pretty well. The last night of my service, the staff warned that the patients were escalating in aggression and left the room to fend for myself. Sure enough, two of my "pals" went head to head and I immediately stepped between them. They towered over me, but I just said quietly "not tonight guys". They stopped in their tracks. I plastered a big smile on my face and we went to claim the last of the treats.
I didn't start shaking until I left the building later. I've done other stupid things of the like, but that one could have gotten me squashed like a bug or resulted in a ward wide melee.
Today, I prefer to use my withering stare.