Bang Bang

!! ensures a truthy return is purely true or false.

a_method_that_is_truthy?
=> (true || false || nil)

!!a_method_that_is_truthy?
=> (true || false)

Must remember to use this.  It ensures the return value is explicitly true or false only (no nils) by first negating the value - which turns nil into true - and then negating it again.