The Virtual Boy was a brave attempt by Nintendo to bring virtual reality gaming into homes. Sure, it was a thundering failure, but innovators deserve some credit regardless of the commercial outcome. Hooking up and playing my Virtual Boy for the first time was a good experience, and all rumours of headaches and discomfort I had heard previously were true. What I liked though is that Nintendo knew very well they had walked all over ergonomics when they released it.
The Virtual Boy manual clearly reveals that they knew they messed up. Pages and pages have so much red warning text it feels like you're playing the console. Almost every section has warnings of some kind; "don't play it in the car", "if you use pirated games, you'll get nauseous", "wear your prescription eyeglasses", "don't make it too loud".
They even went as far as creating two types of warnings. One is called "warning", and the other "caution". Cautions are the lesser evil and they indicate that you may damage the console, or yourself. Warnings are the serious ones, indicating that you may severely injure yourself.
Here are some pages from the manual, for your enjoyment.