Each major grocery store chain has its own ‘green’ (reusable, ‘eco-friendly,’ etc.) shopping bag. The idea is to stop using those staticky flimsy plastic bags that were so shapeless it took no skill to pack them. Hell, the grocery stores let us bag our own if we got in the right line-ups. (Were the Bag Your Own lanes supposed to be a reward for something, in the way that having “less than” eight items allowed you to use the Express Check-Out?)
But my point is that with these new bags and their squared bottoms it’s time to revive the Lost Art of Grocery Bagging. Or at least make a rule that bread does not go on the bottom.
Terry Murray 
Grocery clerks definitely need training on these things. The prevailing thought seems to be “fill until completely full,” at which point the bag weighs somewhere in the vicinity of 45 lbs. I give you 4 bags, please use them all. I have to walk home!
The checkout people seem to put like things in the same bag — sometimes it’s, like, all tinned goods, or all bottles. But mostly it’s all heavy stuff. And of course any squishables go on the bottom. Or at the top of an overstuffed bag (the handles do the squishing then). But maybe the people bagging the groceries have such great upper body strength (from scanning & bagging groceries) they have a different sense of what’s heavy…