Pay attention! Have you told yourself that recently? I have. Sometimes I can't stay focused on what I'm writing on my novel and end up jumping around and saying "what if's". Other times, I draw a blank, and go no where. Every time I stall I kick myself mentally and talk to myself. The times that hurt are when I don't and waste my time dreadfully.
To help I began to make a list of the comments that I tell myself while writing. I keep the list of quotes by my writing desk where it is very visible. Each time before I write, I look at the list and I find it is easier for me to stay on track this way. I do say, I never thought I'd be quoting myself.