I have seen some unfortunate cosmetic dentistry. How on earth do people let their dentists talk them into it? Like Hilary Duff and her Chiclet-sized dental veneers, which she finally got resized after people started making wisecracks about them.
I don't know why people go overboard with bleaching. I do a modest amount - I use bleaching toothpaste (Rembrandt Intense Stain) with a Sonicare toothbrush and everyone remarks on what great teeth I have. The dentist is always amazed that I have zero plaque and calculus on my teeth. But bleaching them to not-found-in-nature levels is just creepy, I agree.