[gnulinux]

Imagine writing code for an elevator. If there is a glitch in your code such that when the date changes from 1999 to 2000 it'll release all the ropes... that'd cause bunch of people to die. Something like this is exceptionally unlikely, but if you're writing code for a real life device you should always always think about its implications.

Read this: https://en.wikipedia.org/wiki/Therac-25

This Radiotherapy machine had a software bug which caused 6 people to be given massive radiation overdose.