 Did you notice how your thoughts coiled back on themselves, how you went in circles as the night wore on? All of us, even those who have been spared the pain of insomnia, have heard that voice. If you've messed up a presentation at work, or flubbed a test at school, or been rejected in love, you've heard those nagging, doubting thoughts burrowing themselves deeper and deeper into the recesses of your brain. Ugh, how can I say something so stupid?