Once decided, it's not ok to think
If you have decided that you have 100 problems to solve in the next week and that it is the priority, thinking about its importance is one of the crucial things preventing you from getting it done.
When you get to work, you don't think about how many problems you are going to finish at one sitting, or if it's a right time to sit and do the problems or what is the best time of the day to do the problems. The activity isn't a marathon, it's a one week drill and you gotta sprint whenever you have time. Therefore, whenever you are not sleeping/eating/shitting, you've got to be solving some of those 100 problems. If you rationalize and (again) give yourself time to think about how important it is to do those problems...blah blah blah; You will not get started or you will not get the momentum to do the 100 problems in a week.
So, don't give yourself time to rationalize, just take up the problem as you get to work. Think twice/thrice before deciding, but don't think again once decided. Rationalizing or thinking about what's already decided makes you confused and the importance of that job decreases the more you think about how-important-is-this-job; coz if it were really important, you wouldn't be perpetually thinking about its importance.
So, don't give yourself time to rationalize, just take up the problem as you get to work. Think twice/thrice before deciding, but don't think again once decided. Rationalizing or thinking about what's already decided makes you confused and the importance of that job decreases the more you think about how-important-is-this-job; coz if it were really important, you wouldn't be perpetually thinking about its importance.