I don't organize them with a mind as to how they'll be bagged, but I usually put vegetables down first as they take the longest individually to process and put fragile things like eggs last.
What I do wonder is if the cashier is judging me as to the quality of my purchases. Like if it's all fresh vegetables and grains do I get an A? If I add in a frozen pizza does the score drop to a B-? If it's just trash like chips and processed junk do I get a D?