Last week, I was assigned to fix a bug in my first project in my current company.  The said application was released months ago and is currently being used by our client.

Initially, the fix was just to move a particular line of code just above a conditional statement.  I am all set, ready to commit, but then I chose to do the checkin dance and run the test suite.  RED! - it's broken.  Good thing my teammate included the now broken test method, otherwise, the bug would have taken a longer time to surface, either on our territory or worse, with the client.  I remember dealing with this scenario in my previous projects without automated unit tests and continous integration setup, it was hell.