I just read a great quote someone posted in response to a question about fear on COTH. I thought it was worth posting...
"I remember an interview with Pippa Funnel who always asked herself, "What the hell am I doing here?!" before going out at Advanced. Or, Matt Ryan who was notorious for vomiting due to nerves when he got to the start box.
Fear is not a bad thing. It is what you do with it."