I have several...
[spoiler]I've lied to just about everyone I met. Even friends.[/spoiler]
[spoiler]I lost all emotions due to personal experiences. So I just fake everything.[/spoiler]
[spoiler]I tend to talk to myself a lot.[/spoiler]
Not gonna post secrets here, but several years ago there was a really cool social movement where you would wrote a secret on a postcard and send it anonymously to PostSecret. Then they were published into books, and I think there was a website too.
Some of them were funny, some really moving and emotional.