So you get a phone call - "E-M-E-R-G-E-N-C-Y, the monitor program you wrote doesn't work - we don't see results". You get there, flop around, wondering why something just stops working like that.

Maybe it's a hardware problem... wait, the communication card doesn't seem to be functioning. Lets connect a few cross-wires to test it - hmm, that's it, something is wrong with the card.

"Er... we kinda had a lightning strike here last night and a few systems fell".