For me it was sitting in traffic watching people on their bikes around me in Toronto. I had biked everywhere as a kid and for me too it was the best way to get around in university, but as an adult I got caught in the rat-race car-commute grind. I'd be driving to get downtown and right near me would be people on their bikes in the summer. At stop lights or whatever I found myself staring at them wishing I was on a bike, remembering how free it felt when I was younger. Took me a few weeks to muster up the courage, and once I did I couldn't believe it took me that long. :). Wouldn't have it any other way now!