Two stories:
YOUNG AND STUPID.
I was a freshman in college ('77). I had a dorm room facing a courtyard. It was just before spring break. People were shooting frisbee and hanging out on the courtyard. I decided to impress them with my vinyl collection. So, I had Pioneer sx737 receiver, a pioneer turntable and nice set of KLH speakers. I went to move one speaker over to a lower window facing the courtyard that opened towards the inside. While balancing the speaker in one hand and propping open the window, I dropped the speaker on the metal corner of the window and put a huge 2 inch gash on the side of the speaker. My heart went through the floor. I mowed many a lawn to earn those speakers. And I trashed one.
OLD AND STUPID.
Although this involves a guitar and not audio gear, I was trying to line up two hand made classical guitars side by side to compare neck profiles. Not being satisfied with the placement of one, I tried moving it by slightly grabbing the bass bout on the front and the back with one hand. As soon as I gripped it I heard a slight "click" sound. Again, my heart dropped. The pressure cracked the red cedar top at the rear bass side. A 5k guitar, cracked by a mishandling idiot.
Brain farts happen. I'm sorry for yours!