You know how a diabetic needs to keep a quick source of accessible sugar? I keep a quick source of accessible wins: my "to be implemented on a rainy day" A/B testing notebook. If I feel like programming and have programming scheduled but just can't get started for whatever reason, I pop one of those little candies of coding goodness to grease the wheels. At the very least they'll force me to get my IDE open, fire up a test suite, bang up some code, etc etc. After one is done I often feel that, since I'm already programming, I might as well go on to do whatever I really planned to do today.
There are days when I just can't program. We've all had that day, right? If I'm in mental shape to do other work, I do other work. If not, I shut down the machine and go out. (I can't wait until this doesn't require apologizing to my coworkers for taking the day off.)
Cory Doctorow has a saying for his writing students: "Surgeons don't get surgeon's block."
I think the point is that the idea of professional block is just a fancy name for procrastination. However, I don't think he did any actual research with surgeons, so I can't say whether they procrastinate or not.
Surgery is not a creative process, at least, most surgeries shouldn't be. Instead, surgeries should be performed by somebody who learned about the procedure in medical school, and then performed it multiple times.
A well known poet (I forget who) taught creative writing for years at a small Midwestern college (I forget which). His rule was that his students had to write a poem a day. One day a student said, "Professor X, I'm trying to follow your rule, I sit down to write, but I just don't get any inspiration. Do you have any advice for me?" His reply: "Lower your standards."
There are days when I just can't program. We've all had that day, right? If I'm in mental shape to do other work, I do other work. If not, I shut down the machine and go out. (I can't wait until this doesn't require apologizing to my coworkers for taking the day off.)