I almost did it...

I typed up my letter of resignation.  I even printed it.  Had it sitting here on my desk while I worked all morning and afternoon.  And here I am 20 minutes before I go home, having just gotten out of a 15 minute meeting about my "future" with the company and somehow the letter is still sitting on my desk.  I couldn't do it.  I didn't do it.  What am I so afraid of?