Rails — create and create! methods, RoR 3 Tutorial

Question

So I know the distinction between the bang (exclamation mark) and non-bang methods usually is whether the method will modify the object itself or return a separate modified obje

Answer 1

Though a lot of classes treat bang methods as "a method that modifies the object in place", I like the description of bang methods from the Eloquent Ruby book better:

In practice, Ruby programmers reserve ! to adorn the names of methods that do something unexpected, or perhaps a bit dangerous

So in this case, the "unexpected" result is that an exception is raised instead of just failing and returning false.