Because it wastes so much water and I think the shower water is too warm for good shaves, I also don't like the idea of shower shaves.
That being said, any cheap mirror becomes fogless by simply lathering it with a bit of soap or goo when you start the shower. By the time you need it, the lather has run down the mirror and the rest stays fog free (for the most part).
Razors don't shave people. People shave people!
There are three critical types of moments in life: Times when we should use opportunity to be enamoured with finer details, and times we should ignore the minutia.