Stop answering the door when someone knocks. It's never anyone you know. Everyone you know would call first and not show up unannounced. Usually it's some pothead trying to scam you into buying magazines, or better yet..they want your help in earning "personality points" which is a not so creative way of trying to scam you into buying magazines. These people are relentlessly annoying. Remember that crackhead a few weeks ago? The slacker who was high? The one who didn't even try to make his paperwork look legitimate? (Where there was to be a picture of him, he drew a smiley face.) The one who started getting mouthy when he caught wind you weren't buying into his scam? That same jackass was at Karen's apartment yesterday trying to pull the same frickin' scam. Remember him and the ones before him next time you hear a knock at the door. Ignore it and just continue what you are doing.