The worst advice I've ever been given was "be yourself."
In America, you're told to "be yourself," to "be unique," but from the very first moment you show any signs of differing from the social norm, you're shot down, ridiculed, or worse. The popular fad of today is calling anyone who has even the tiniest bit of individuality a "snowflake." I've seen this a lot on YouTube, mainly from young people, too. It's very depressing and has pretty much killed my hope that the human race was progressing beyond such things.