I had a much better shift today, didn't run into any nasty problem bikes but I was getting **** done and staying on task.
I'd give myself an expectation of how long the job should take me and tried to keep within those parameters as best as possible. Dividing a service up into 10-30 minute intervals for each part of the job was a big help, I knew when I had time to spend a bit longer on a problem or when I had to hustle a bit faster.
Keeping a clear mind and only thinking about the job instead of what I was doing after work was a big help as well.
Thanks everyone for your advice, warms the cockles to have a helpful community of mechanics in cyberspace like this