I'm 34 and I remember being left alone in the car all the time while my mom ran errands or whatever. I specifically remember a time when I discovered how the cigarette lighter (remember those?) worked when I burned the tip of my finger on it while my mom was in the post office.

I rode my bike all over town. Several times my friends and I walked across town to the video store by ourselves, rented a Sega Genesis and a few games, and hauled it all back to someone's house and stayed up all night. I was probably around 12.