Our startup was based in the garden office of a large house and the production server was situated in a cupboard in the same room.
The day I started was a cold January day and I’d had to cycle through flooded pathways to get to work that morning - so by the time I arrived my feet were soaked.
Once I’d settled down to a desk I asked if I could plug a heater in to dry my shoes. As we were in a garden office every socket was an extension cable so I plugged the heater in to the one under my desk.
A few minutes later I noticed that I couldn’t access the live site I’d been looking through - and others were noticing the same.
It turned out the heater I was using had popped the fuse on the socket. The extension I was using was plugged into the UPS used by the servers. So the battery had warmed my feet for a few minutes before shutting down and taking the servers down too.
And that’s how I brought production down within 3 hours of starting my first job in the web industry…