Faced with one or more bottom-up thoughts (shown in green) in your awareness wheel, you will likely find that your attention will naturally flit between them. You can consciously overpower this, and drag your focus to a top-down task that you want to prioritise (a blue task). 

When boredom kicks in though, this resolve will weaken, you lose control of your attention, and the compelling thoughts will win over. Once boredom is lowered, your resolve is restored.