What's your most expensive mistake so far

I'll go first... Was putting back rocks tumblrs (about 10 bucks each) onto the tray after polising them. The tray had over 2 dozen of them and they were stacked towards the front. I pulled the tray bit too far which caused the entire thing to topple infront my eyes in slow mo. Five dustpans of shattered shame. My manager was chill about it though and made sure I wasn't hurt. I am however, considering buying a new set out of my pocket for the venue. Feel like shit!

Would love to hear your stories