Not quite so disastrous, but still pretty dumb. I was logged in over VPN to a client machine. I suspected the problem I was fixing was something to do with the

Not quite so disastrous, but still pretty dumb. I was logged in over VPN to a client machine. I suspected the problem I was fixing was something to do with the network misbehaving. It was a Windows machine. I thought "I know: I'll disable and reenable the network device!". A few moments later: "Oh. Bugger.". Shortly followed by an embarrassing call to the client's IT department to ask them to reenable the network device on that machine...