Imagine you’re invited to dine with the president or your favorite sports star, or say a natural calamity strikes. Will it change your existing engagements for the evening? There’s a very high probability that it would. Similarly, all application and OS threads that execute on a system are assigned a priority (default or explicit). Usually threads with a higher priority are preferred to execute by the thread scheduler. But this preference might leave threads with a lower priority starved to be scheduled.