I always answer the door - I'm too nosey to not see who it is!
A couple of weekends ago someone rang the doorbell and I was about to jump in the shower, and had nothing on, so just threw my dressing gown on and answered the door to be confronted by 2 Jehovah's Witnesses who started being very chatty. I reached down to get Smudge away from the door and realised they could probably see down my dressing gown at the top, so quickly jumped back up and use my (bare) leg to get Smudge back and they got all flustered, and they said "thanks very much, have a nice day", thrust a flyer at me, and hurried on!
I remember a while back I knocked on a neighbours door around the middle of the day on a weekend to check the time of his party that night, and he answered it wearing nothing but a towel.
And as it turned out he had a MIGHTY fine body!!!!!!! I was red and stammering and didn't know where to look. And he was one of those ultra nice, ultra polite people who always said "do you want to come in" whenever you knocked on the door, and he said it and I hesitated for half a second before saying "no it's ok, I have to run anyway..."