This book just made my heart flutter. Called "Everyday Engineering" it examines the engineering and planning that goes into the world around us. As a self-taught engineer this is exactly the sort of subject I spend hours thinking about.
A memory that always sticks out in my head about discovery is being a kid and sitting in the front seat with my dad as we drove along a paved mountain road. I had noticed the reflectors were buried beneath the surface of the road, with a slope cut in the direction the oncoming traffic so the reflector would be visible.
For miles I stared at these things until it finally dawned on me what they were for. Since I grew up in the middle of California's Central Valley, snow is not a typical occurrence. The reason the reflectors were buried beneath the ground is so that snow-plows can scrape the surface of the road without ripping up the reflectors.
It was incredibly pleasing to have come up with the solution, and I still spend a lot of time staring at structures to determine why and how they work.