I had one of those times in response to a fear attack. Years back, I was riding along quite nicely, when behind me I heard this almighty shout and suddenly two alsation dogs were on my heels. I tried to ride as fast as I could but my legs instantly turned to jelly - so much for adrenaline, eh?
I had to quickly dismount and put my bike between me and the dogs. One of them, for a reason only it knew flew at me in attack mode. Fortunately, I was able to hit it with the bike and it backed away. The owner came around the corner and called the dogs to heel, but he was more pissed off with me than he was with the dogs. The adrenaline suddenly kicked in and I wanted to take my bike and smash it over his head. I rode away almost with the shakes - not a great ride.