CodeMonkey makes error..

The codemonkey writes boring program code as he watches an episode of Weeds.
Error compiles and avoids detection during unit testing. System is delivered to customer(aka suit). Codemonkey is happy since he now can engage a more challenging project.

Suit on the other hand is pissed of At codemonkey. The system does not meet requirements. The system failures to often.

Codemonkey receives an error report from suit. Now codemonkey is unhappy. The Error who led to Fault and to Failiure is corrected. Suit and codemonkey go to bar and drink rootbeer.

Error(syntax misstake or not met requirement)
Fault(system crash during testing/development)
Failure(system crashes or incorrect output from system to suit)

All according to IEEE,729..