A task manager is a computer program whose sole duty is to monitor other computer programs.
To live mindfully is to cultivate a mental observer. This observer resides in our minds and is detached from experience. It observes the movements of our minds, constantly checking how we feel and what we feel even as we immerse ourselves in an experience.
When a mindful person reaches for a cookie during a diet or is about to scream at a customer service agent, their mental observer intervenes. It alerts them just like the task manager does when a computer program goes off the rails.