Office Pet Peeves Week - Day 3

The closed door pet peeve

I rarely close my office door - if  my door is closed there are 3 reasons for it
1) Someone is in my office and we are having a confidential discussion
2) I am on a confidential phone call
3) I am extremely busy trying to meet a deadline

98% of the time, my door is open.

However, it never fails that when I shut more door the following happens

Scenario 1:
Rude Employee: * knock, knock *
Rude Employee: opens door before I say "come in"
Rude Employee: Proceeds to ask me a question or tell me their problem even though they can clearly see I am in the middle of a meeting with someone else because the other employee is standing right in front of me.

Scenario 2:
Rude Employee: * knock, knock *
Me: No reply because I am on a phone call
Rude Employee: * knock knock knock knock knock knock * (and louder)
Me: No reply because I am talking on the phone
Rude Employee: opens the door anyway (although I didn't say "come in") and says "Oh, I didn't know you were on the phone" - I will just wait
Rude Employee: Sits down in my office and leaves the door open.
Me: I have to tell the person I am speaking with to please hold, then tell rude employee that I will see them when I am done with my call
Rude Employee: But I only have a quick question.

There are many others I can list but these are the 2 main issues concerning closed offices doors.