I was coding PHP for a living, and then heard of their change from :: to \ as a name-space separator. I'm really not joking or being spiteful, but that is really what got the ball rolling.
Not to be elitist, but I suddenly realised that the people I had to collaborate with whom knew PHP understood very little in programming concepts in ways that frustrated me how they could be so blind, the people in the IRC rooms for it were no longer a source of help for my questions, and I usually spent more time answering questions and waiting for somebody to turn up whom could answer mine. Usually I ended up solving it myself.
Most the time I realised was people re-solving the same problems over and over again in increasingly bad ways.
I discovered problematic behaviours in PHP which defied logic and reasoning (like the array_merge_recursive family), and discovered functions that were undocumented in how to use them, and when I reported a bug in the functions, my bug was marked as "Bogus" and I was expected to be psychic.
I had a friend whom was constantly proclaiming the goodness of Perl, so I basically gave it a shot and now am hooked like an addict.
Additionally, my experience in other higher-order dynamically typed languages (JavaScript and Ruby, yes, JavaScript is a more powerful language than PHP in terms of language features) left me a knowledge with many ways to solve types of problems easily, but being restricted in such a way I had no way to use these powerful features. Perl satisfied this need.
Why Perl and not Ruby? I've played with Ruby a bit, but my experience taught me the support and documentation is sparse, the language is slow and immature. Nice it may be, but its still in diminished in capacity against Perl from what I've seen. And it shared PHPs major flaw that it has a huge user base comprised of total novices all doing things the wrong way, and I really wanted to not have to deal with that so much.
It's not nice to be elitist, but once you have tried to explain the same thing to 30 people (and taken an hour to get a simple concept into their heads every time) it reaches a point of frustration. (I can't cope with the 'There is somebody on the internet who is wrong' situation, If I can't SEE it, it doesn't happen)