Then I started listening to this podcast called The History of Jazz by Georgia State University professor, Dr. Gordon Vernick. (Look it up. Wish I could link you to it directly.)
I also started reading my co-worker's copy of Paul Arden's book It's Not How Good You Are, It's How Good You Want To Be.
And on a bright sunny day, I accidentally took the bus too far and had to walk through a couple of neighborhoods I'd never explored on foot.
And suddenly, things were awesome. I liked work. And I've been very productive since.
If you're stuck, frustrated or down on work, it's not enough just to take a break. A walk around the building or a trip to the burrito joint across the street can sometimes help. But you really need to change your routine.