Why should "any" OS be a mistake? Don't people ever get tired if this useless and meaningless discussion about what OS is good and what OS is evil? Just use the OS that you like, understand, can afford, is mandatory for your work etc. I use an MS OS for my work since MS DOS (and starting to use a PC)and "toy arround" with Linux since the first free Red Hat distrubution. So what?
I am a happy user of PC's and so are many MS OS and Linux users. Try to be helpfull to others with the OS you understand and don't bash others.

Regards Evert