Valorous Visitation of a by-gone Vexation

I don't understand why some people likes to begin without having an end in mind. If you offered to do something, why don't you be thorough about it and finish everything instead of doing 99% and leaving that 1% behind for someone else to clean up after you? I mean, you have already finished 99% of the work, what is the point of leaving 1% unfinished? What is your rationale for doing so? I simply cannot understand.

If you have no intention of finishing the task, then why volunteer in the first place?