Dear mumbling lady from the grocery store:  I am sorry my door is in the way.  I am in the process of changing my baby's diaper, and I will just be a moment, which I did express to you with my "excuse me" and "just a minute".  I saw you, and I knew you were there, and I did hear your insistent tone.  You are able to use both sides of your car, I assure you.  Both doors work, though the other side "is locked."  I am only able to get my baby in on one side of the car.  Sigh.  I wish you hadn't been quite so snippety with me and my baby.  It figures that the lady I avoided in the store because she was talking to herself and plowing down the aisles would be the one who's car would be parked right next to mine.  I would like to add that I had to wait quite a long time for you to get out of the parking spot, but I hope that I wasn't too impatient. 
Signed, the lady with the 3 children trying to get everyone strapped in and clean in a timely manner.