It’s like preemptively slamming your door in someone’s face
If you don’t have a moat and drawbridge in front of your house, you need something to let people know how you feel about interruptions. As Jean-Paul Sartre cheerfully said, “Hell is other people.” When we read that, we thought it would make an excellent “welcome” mat! Okay, so maybe it’s more of an unwelcome mat, but those have their uses too. If you know a grump, put this 22-1/4” x 14-1/2” PVC mat outside their door to warn visitors that the person inside would rather be alone.