Yak Shaving is when, to complete a task, another task is required first, and then another before that, ad-finitum. Such that the chain of things needed to do to complete the original task becomes unmanageble.
I want a cup of coffee. But I have no milk.
I can get some milk from Mike, but if I ask him, he will want the $5 I owe him.
Pete owes me $5 that I can get from him first, but he will want his pillow back.
I have his pillow, but the filling has fallen out. It was stuffed with Yak Hair, so I need to find a Yak.
There is one at the Zoo…. and so on…
Yak Shaving can either be and end result where by you require a simple end point, but the path becomes too complicated to get there.
Or, a method of procrastination, where someone keeps putting small “pre-requisite” tasks in front of the main objective and never make it to the end.