well... lets see....
1) i have dropped lights a few times on my girls... i have my lights in rows, so as i raise a light the entire row raises... it was 2 rows of lights i dropped.. and 1 of the times i dropped them 3 times.. fortunately all the girls made it..
2) i nute burned the shit out of them... it wasnt actually my fault.. my drain pump froze up and my system was flooded for 2 hours right after a nute change.. yea... that was bad... lost more than a few of them..
3) was doing some reconstruction to my grow room, had to remove the a/c because of the fresh air intake i was doing, which caused a heat spike in my grow room.. which happened, ironically, during the hottest week of the summer... so i was cooking my girls with 100 degree temps, while watering them with 90 degree water while i was waiting for my water chiller to arrive.... somehow they pulled through that..
4) i think this is the worse.. some how during a grow early in my career i missed a male.. during flowering the male just happend to be in front of the damn oscilating fan i had going... it completely ruined an entire crop with seeds... it broke my heart...