My parents were architects and my sister and I lived our first few years in Honolulu before moving to the SF Bay Area. There were no billboards in Hawaii, and I recall distinctly the first drive from SFO the the East Bay. I was unable to avoid reading and staring at every billboard next to the freeway and it literally made me throw up. I didn't understand what was happening.

Of course, I was quickly conditioned off of that response to billboards, which I consider natural.