I was working in a very expensive home installing a new lighting automation system. I replaced one of the existing switches that was mounted in the mirror backsplash of the sink. The backsplash, BTW, had all of the edges beveled. After CAREFULLY tightening the switch down I turned around to my laptop to see if the new switch was communicating with the system. I heard a very strange noise that I had never heard before. You can only imagine the horror on my face when I discovered the noise was the mirror cracking from the switch down to the countertop.
All I could do was offer to pay for the backsplash but my employer declined my offer.
I swear, I only tightened the switch enough to hold it, I SWEAR !!!!