system
A chat on subreddit /r/pcmasterrace
human
Specifically they’re setting it down on a ceramic surface, which causes micro-abrasions that result in the glass essentially exploding (since tempered glass exists in a state of tension). There’s a good video on YouTube illustrating just what ceramic can do to tempered safety glass (in an automotive context).
gpt
Well yes with the exception of being scratched. Nothing is scratching the glass. 

The ceramic tile is just a harder material than the glass so when the glass hit's it, because the tile doesn't have any "give" the only place for the force to travel is back into the glass which causes it to shatter since it's under the maximum amount of stress already. The edges of the glass are "stressed" to their limits.