It wasn't a co-worker, but a contractor that got me to make the switch. He was helping us move our network, and I happened to walk into him just as he was exhaling. He was a stealth vaper, so I didn't realize he was even vaping at first. Not that I would have cared, but I thought it was kinda ballsy to be smoking inside.

But I figured it out, asked him a few questions about it, and eventually started researching it on my own.
Now I've got two weeks sans analogs under my belt. Now that I think about it, I may have to send him a small thank-you for Xmas.