Replaced my old 90s Peugeot mountain bike with something more modern in 2010 because I thought the four mile commute to work might be fun.
Then I discovered how much I like long distance riding. Ended up liking it so much I rode the Seattle to Portland yearly event five times.
Then I ended up riding across the continent from Seattle to central Florida while laid off, just because it seemed like it'd be fun. (It was!) Eventually was commuting 20+ miles to the new job, though I did take the train in the mornings, I'm not that much the masochist.
Now I've got 39 titanium implants because some asshole ran a red light rather than look up from his phone, snapping my left femur, breaking my pelvis, turning my left tibia and fibula into a jigsaw puzzle, and exploding my right femur's condyle, so that little whim to try commuting by bike didn't lead to only sunshine and roses.
On the other hand…because I did have the thought 13 years previously that commuting to work by bike might be fun, I was in such extraordinary shape when the car hit me that even though I'm in my mid 50s, I went from wheelchair to walker to cane in months, and was back on the bike within a year.
"I should try commuting to work by bike!" Hoo boy, what a ride—if you'll forgive the pun—that little notion set in motion.