I do think a lot of people could stand to be more "situationally aware" to avoid inconveniencing others. If she had thought a little about those she was holding up, the outcome would have been very different.
Along this line, I nominate this woman at Target yesterday. It was very crowded and each open line was three-four people deep (there were a lot of open lines, too, at least 10). This woman in front of me has a full cart of clothes. The SS part was that she took each one off the cart, asked the cashier to ring up the price, spoke with her companion at length about whether they should buy this item, and then repeat for the next piece of clothing.
I ended up moving to a different line, and by the time I checked out she was still at it, and the cart was at least half full.