The last 10% has little to do with the number of remaining items, and all to do with the type of tasks and mental blocks. Project fatigue sets in. Within the l

The last 10% has little to do with the number of remaining items, and all to do with the type of tasks and mental blocks. Project fatigue sets in. Within the last 10% are small details pushed aside as the pace was chugging along for the other 90%. Seemingly trivial problems are hidden until the end, during which, developers/engineers are most eager to move on to the next mentally stimulating new project. I think there is a reason why in schooling, 'A' level work requires a completion of that last 10%.