Personal Experiences: (Dates may be slightly off)
1989 - During an Ultra-relay in NH, I was anchor leg. The top 8 teams got medals. Of course I was in 9th when I headed out. The last leg ran up a mountain to a ski lodge. Teams supported teammates by handing water to the runners throughout the course. Anyway, I had passed the team in front of us and moved into the medals but the other guy was still close. The next time I got water, the other team drove around the corner just after I threw down my water bottle. All they saw was a teammate running next to me. At the next water stop, my team and the opponents were screaming at eachother about pacing (which never happened) As I grabbed a cup of water, one of their team was came onto the road yelling at me. I threw my water at him and told him to "Go FU#$ himself!". Then I put my head down and buried their guy. After the race when we realized a masters team was ahead of both of us. They apologized and admitted they didn't see the water bottle I had tossed. In the end, both teams got medals.
1992 - I got into a fist fight at the World XC Champs in Boston. My club was give the 'prestigious' Bear Cage Hill to monitor. A photographer snuck up onto the hill (not allowed by the IAAF) and tried to get on the course. After repeatedly trying to get him to leave - he decided to shove me. That's all I remember. My friend Rich pulled me off of him. I had the imbecile on his back in the mud and snow and was swinging away.
1996 - At a 10miler, it was very windy. A group of 8 formed to run about 53min. Myself and a friend switched leading the pack into the wind for the first 4 miles. At that point, I pulled right and looked at the 'suckbags' and screamed "Come on you guys... it's not that fuc$in' bad!" After this same bull$hit continued for a while, the two of us put our heads down and dropped the group. There were people in the group that I very rarely beat. But the adreninline was pumpin'.