leave something at the door

Mark Zuckerberg clearly thinks China is worth the trouble, even if that means leaving some “Western values” at the door.


Mark Zuckerberg is determined to launch his social network in China, whatever it takes
The Chinese government likes to control social media and what people do with it—but Facebook looks willing to launch in China anyway.
TECHNOLOGYREVIEW.COM|由 EMILY PARKER 上傳

Question
Hello,
What is the meaning of the expression "leave something at the door" in general and what does it mean in the following sentences?
1. I don't care if you had a fight with your boyfriend before coming here. When you get to work, leave your troubles at the door and focus on your job, not your boyfriend.
2. I am unable to stop thinking about work, even after I arrive home. I have to learn to leave work at the door. 

Answer
You leave worrying about whatever it is when you go in the door at work or at home.  When you go in that door, you focus on what happens there, not what has happened elsewhere.

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When you get to work, don't think about your boyfriend and the fight.  You're at work now.  Focus on your job, not your private life.

I have to learn to stop thinking about work when I arrive home.
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