Because nobody in real life is impressed by your level 160 elf mage.
When most people say "I don't care what other people think", it's not really true. It just indicates a mismatch with the audience under discussion.
Look at Steve Jobs or Mark Zuckerberg; you think they care what others think of themselves as a person?
You mean like the zuck arranging to announce a $100M donation live on oprah a week before the social network hit theaters?