If there is a delay on a highly coupled task, then pick up on uncoupled tasks that you could do while you wait.
Some low-energy and uncoupled tasks are probably always available: accounting, inbox zero, file organisation, scheduling, daily review, weekly review, self-analysis questions, etc. Unless a YouTube video was on your task list, then it is distraction working against you, not for you.
From @balupton and @ExplorerSumit