I'm thinking substance abuse or head injury ;-)
Seriously, it was Perl's easy availability, the whole Perl philosophy as I understood it then (mainly from things Larry Wall had said). The idea that I could actually get things done without having to learn everything about the language. CPAN and PM were also important, but I didn't learn about them right away. Mostly it was that Perl would let me just get started without having to declare all my variables (or any of them), without having to create a main routine, without having to announce to the world every last module I wanted to use (until I figured that part out). It fit in with my way of thinking, which isn't nice and linear like some peoples', but tends to wander around on the way from here to there.