Four years and three months ago, I started working at the National Post. It lasted about four years and two months longer than I expected it to.

Truth be told, I more or less shared my friends' view at the time. I'd applied for the job on a lark, and accepted it because I was flattered the paper actually wanted me. But I fully expected it to end badly.

As anticipated, it was a rough adjustment. In the early-going, I'd occasionally come home from a day of work and suffer a fairly melodramatic existential crisis, wondering what I was doing with my life and just how badly I'd sold out. My bosses must have had their doubts as well: Rather than hiring me off the bat, they put me on fairly heavy probation. I started a trial run on a day-to-day basis, then week-to-week, and then month-to-month. Only once I'd been around for nearly half a year was I offered a full-time, long-term gig.

Accepting it was one of the best decisions I've ever made.

The biggest knock against modern opinion journalism – especially in its online form, but also when it comes to print, television or radio – is that commentators divide into ideological camps and rarely venture out. Liberals work with other liberals and write for liberal audiences; conservatives do likewise. Liberals make little effort to understand conservative views, and vice versa; instead, they oversimplify the other side's arguments and demonize those who make them. As a result, neither the commentator nor the reader winds up challenged; instead, they simply have their own views reinforced.

I was guilty of that approach, at least to some extent. Having run an online magazine that published a smorgasbord of views until 2002, I hadn't been too sheltered. But from the outside, I still had a cartoonish image of the Post as a heart of darkness where a bunch of cold-hearted conservatives sat around plotting how to screw over single mothers and turn Canada into the 51st state.

Perhaps there really were one or two of those people. But I mostly found was a group of people who were bright, thoughtful, and genuinely committed to building a better society.

That we had very different views on how that should be done led, over the past four years, to no shortage of internal debate – a sample occasionally making its way onto these pages. But having to defend my views to smart people who opposed them forced me to realize which ones I really believed in, and which I'd adopted because it was the right thing to do in the circles I'd previously moved in. My positions on issues became more nuanced; occasionally I found them changing entirely.

I'd worried, early on, that my sense of liberalism would be eroded by working here. And by some definitions, I guess it was – I'm now more open-minded on health care reform, for instance, and more critical of government waste. But in the end, I take it as a point of pride that my outlook can no longer be summarized in a single word – that readers (hopefully) don't know my opinion before I've written it.

I'd like to think I had an equivalent impact on my co-workers, though that would probably be giving myself too much credit. But it says a great deal about my colleagues that they were willing not only to accept me into the fold, but to hear me out and to give me space that I often used to air views that they – and many of our readers – disagree with.

When I started telling people a couple of weeks ago that I was leaving the Post, many of the ones who looked at me funny when I started here gave a similar response now. Good thing, they said – I never really fit in here to start with, and I must be relieved to finally get out.

Nothing could be further from the truth. I'm leaving for the same reason most people leave jobs – because there's a challenge elsewhere that's good for my career. But I leave with a great deal of fondness and a whole lot of respect for the men and women I've worked with for the past four years – not just because they're good people, but because they've made me a hell of a lot smarter.