One of the problems I you'st to have getting through my working day was in under estimating the time it would take to complete a task. I now build in a 'comfort' time so that when inevitably things go wrong, I should still have time to complete. Having established that I am going to get lumbered with a difficult task, I let my brain get on with other important things until required to tackle the 'difficult' task. Somehow, once I get involved in the task, it never seems as 'difficult'. All in the mind.!