It's wrong to invade other peoples personal space.
Becca is sitting quietly in her room with the door shut, reading a book.
Becca's roommate Jen wants to talk to Becca about something.
Jen knocks on Becca's door and asks if Becca has a moment to talk.
Jen opens the door and walks into Becca's room without knocking first.
Jen respects Becca's privacy, and Becca can decide whether or not to engage.
Jen invades Becca's privacy, and Becca is annoyed with Jen.