One of Ruby's syntactical peculiarities is that it allows you to end method names with a question mark (?) or an exclamation point (!), aka "bang". The conventions surrounding the use of question-mark method names are pretty straightforward. But the conventions for "bang methods" are a bit more subtle.
If you don't learn the rules for bang methods, you'll be in for confusion and frustration. And you may confuse other programmers in turn. In this episode, we'll demystify when and when not to end a method with a bang.