There are some bosses who give you the task with a fair deadline and trust you to deliver it and then let you on your own. There are also people who give you unfair deadlines and expect you to stay later and get the job done while the actual deadline for that task is not what they tell you.
They usually do this to keep you productive and prevent you from wasting time. This may not work for everyone specially for people who are productive on their own and care about the job.
In the first case you have several tasks at hand and can freely coordinate them and do them accordingly. But in the second case you have to stop what you're working on and keep switching the context to the new task that you're given.
Are there ways to change this behavior? How should one handle such situations?