Throwing a Boomerang
A boomerang is a crafty device invented by the aborigines of Australia having the useful feature of returning to the thrower when properly thrown and its target missed. Of course, if you fail to pay attention, the boomerang could very well come back and hit you. Similarly, failing to catch your exceptions and check your method return variables can also bonk you on the head. Usually the day before release. Friday at 4:45 PM. On the night your friends celebrate your birthday. Without you.
We will ignore try-catch for now since most of our development is in PHP and its API is almost completely procedural. Being a procedural language, pretty much every function has a return value. Some of these are important and some can be occasionally ignored. Which are which?