Nothing spoils my day like having a task that MUST be done. While I have a strong routine, its aim is not seeing to it that must-dos are done, rather it's to tie up my time with easy and familiar tasks so the must-do must be put off until tomorrow. And, predictably, tomorrow there will be no time either. The only way around this is to make a bargain with myself to spend a brief time, say 10 minutes, on the must-do, after which I can return to the routine. Sometimes I find the must-do isn't so bad and I will work on it until it is finished, or substantially so. But just as often, there will be a week or month or decade of 10-minute sessions; eventually they may even become part of the routine.