Dumbest?
As a soph in HS, the afternoons before a CC meet, I would play pick-up games of tackle football, which included some varsity players on a team that ended up undefeated and state champions. I could carry would be tacklers on my back as I ran with the ball, and could have played tackle football. My coach would show up to the park where we were playing and come out of the car screaming at me (and pulling at his hair). He would drive around every Friday afternoon to local parks to find me. I would run out of there on the way home.
As a junior in HS, a big CC invite that we hosted, we got to the line ready to win. We had only 1 loss, and were expected to win state until I got hurt after the sectional. So we were very focused. We did our strides out of the box, and the 7 of us lined up. Then the timer came by and announced to all "15 minutes to race time." Our coach had completely messed up the routine.
As was our custom, we started swearing at him (using the F word a lot), and got out a football and started passing it around. He was going absolutely nuts trying to get the football back (trying to intercept it), and all the other coaches and runners, and all the parents, were silent (probably dumbfounded). When it got close to start time, we gave the coach the football and then won the meet. I ran my best CC race up to that point in my HS career. For us, this was par for the course, as we had only one "legit" CC runner (thin, 9 flat, 14:10 for 3 miles in crap weather). The rest of us could have played tackle football, soccer, or hockey.
As a senior, because of no sports, I ran in some AAU junior olympic CC meets. The district meet was held on the toughest CC course in the state, and I wore spikes. I got a wood chip in my spike element with 1 mile to go, and I wanted to take my shoe off because with each step the chip was causing my leg to snap shut and I thought my knee would blow out. However, there were wood chips everywhere and I would have cut my foot and been bleeding. The last mile was supposed to be the easy part, after going through steep ups and downs and having to jump wooden hurdles, but I was nervous at ruining my career with each step and floated in the best I could. I still won, and ran a fast time for that course, and had I run in racing flats instead probably would have come close to the course record. I was so nervous the entire last mile, and probably should have just taken off my shoe and walked in.
In '88 I got a courtesy invite to a 5k in a track meet that was held as a prep for the Oly games in South Korea. It wasn't because I was world class, but I was one of the only foreigners invited as the country was prepping for the big games. I was running 100 mpw at under 6 min pace, and was ready to run 14:30 or faster on the track. I ran 15 miles the day before and 10 miles that morning, all under 6 min mile pace so as to maintain my mileage. That evening it was 107 degrees on the track, yet I warmed up several miles fast and kept warming up to race time. I was too tired when the race started to get into a good position, and the shorter and better 5k runners boxed me in and then sped up, then slowed down, over and over. I was so tired that I only ran 15:15.