My sophomore year I rebuilt my robot on December 24th and then left for Europe for a month. Came back, and realized that the latex tubing on my lift was fully stretched the whole time, and was now useless.
My junior year I was using a Dremel to cut some C-Channel, the cut off wheel shattered and a bit of it flew into my mouth and lodged in my throat. That was fun.
Had to Dremel cut a Vex 1/8" shaft out of a drive that was stuck, it fell and my reflexes kicked in. I grabbed it and gave myself some lovely second degree burns. Went to my school’s football game with a bag of ice in my hand instead of seeking, you know, help.
One of my team members unplugged the Dremel without turning off the switch, and when I went to use it again I nearly lost my pinky finger on my right hand.
One of the members of the other teams at my school was in charge of making a practice sizing box and made one 19" by 18" by 18". They went to competition and were surprised to find out that their robot didn’t fit.
And my personal favorite:
A third team at my school replaced all of the screws in their robot with bearing rivets to “save weight”. It fell apart very quickly.
At my state competition this year, after some matches, while I was changing out the battery (which was shrouded in the spaghetti of wires I had going on (I have pretty poor organizing skills), I’d accidentally pull out the wires that run the flywheel. Next match, flywheel wouldn’t work. That was until I was picked by Brentwood to be on their alliance when they gave me cable clips to keep the wires together. We went on to worlds only just by a hair. We breezed through QFs and SFs, but at finals, it got hairy. The winning match score in the second final round was 185-188, and at the last second, I pushed in using my pusher bar a regular and bonus ball into the low goal. Referee told me there was a clearance of only 1 millimeter between the balls. I literally came in with the clutch on that match, for we could have drew and went on to a third round.
I remember when I was a freshman with zero experience on a team with other freshman(and a mentor who didn’t teach) we decided to build a 1 bar lift for skyrise. It snapped in the middle of the match, spewing shrapnel everywhere.
For skyrise my team made a scissor lift out of 1x25s, with no bearings or anything to support the shafts, and only two motors powering it. It also was only attached to the base of the robot on one side of the base, so if we moved too much with the lift up, the lift would tip over.
Well this past year one of our Apprentices called our drive chain “railing”. Does that count? hahaha. Let’s not forget about this either. Slip Gear Destruction - Vex NBN - YouTube Courtesy of our CAPTAIN and some of our builders.
Nice question, man!
Our biggest mistake was believing we were “still in the prototyping phase”.
** FOR THE WHOLE ENTIRE YEAR **
We used kep nuts everywhere, because our coach told us only to use lock nuts after we finalized the design, so if we needed to remove something it would be easier to do so. In the middle of a match one of the opposing team slammed into us from the side and it interfered with the slipgear… The robot exploded.
I’m talking an all-out, screeching explosion that left parts all over the field as we struggled to drive what was left around the field. We’re not allowed to remove our robots from the field at the end of a match until the ref gives us permission to do so, but the ref said something a little different this round: “At this time, please remove your robots, and, uh…, any parts it may have left from the field…”
I did something pretty stupid today. I was working on our robot’s program, and I had gotten up and walked away for several minutes to go talk to my team. When I came back to my computer, I realized that when I got out of my chair I accidently moved part of the mouse and its cord onto the enter key, which added several thousand lines in my program while I was gone. I don’t know if you have realized it or not, but RobotC doesn’t let you delete or highlight the text very fast (at least on the computer I was using). It took just about 5 minutes of deleting to get the code back to where it was supposed to be.
, it is such a brilliant idea. saves like 1/4 of a pound on the robot 
hahaha. Let’s not forget about this either. 
