Spending too little time at the beginning and end of a project….
from our experience there is a lot of pressure on Project Managers to “get things going”. People seem to think that Deciding what you are going to do has less value than actually doing – right brain thinkers mainly.
However, I am a fan of the 5Ps (to outdo marketing people in numbers) Prior Planning Prevents Poor Performance.
Spending time deciding what you are going to do and how and then how you are going to measure it and then at the end measuring it affects timelines in a positive manner.
Obviously you have to be reasonable, but the less time you spend planning, the more time you spend working and remediating. Obvious problems can be avoided.