People don't stumble upon anything anymore. People only ever find exactly what they're searching for.
I love shopping in used book stores. I love the musty scent of hidden treasure. I love going into a place looking for, say, Soccernomics, and finding a dozen interesting books on baseball, 2000 Ford Escorts, science, and film history. When I was a kid, I would look through every single comic in the 25-cent boxes at Golden's and discovered all kinds of crazy and interesting things. Later, I would wade through the boxes at CD Warehouse, listening to U2's War for the first time and discovering the depth of Sister Hazel. I kinda wish I'd had a record store in my home town.
It's a shame. We are too busy, with too much to do, and too little time to do it.