Paper or Plastic?

Thanks to Barbara Bretton for her thought provoking Earth Day question on Facebook; "Which is better for the environment, paper or plastic?".
It seems there is some controversy going on, because paper uses trees, and plastic hangs around landfills forever.
Barbara's commenters got off on a tangent about cashiers and baggers giving them the "stink-eye" and the heavy sigh when they ask for paper, so I endeavored to explain why that is, and  then I thought, "Why not make a blog post out of it?".  Here's my answer to Barbara and her commenters, and then we'll get into the rest of the post:. 

From the other side - Paper is WAY harder to deal with when you're bagging than plastic. The stores don't give you any framework to sit paper bags in, like the holders we have for plastic, and that's why you get the "stink-eye" and the heavy sigh when you ask for paper. As a cashier, when I don't have a bagger available and you ask for paper, it slows me down getting to the next customer, and these days, I'm on a timer. If I don't get to the next one fast enough, it's a demerit on my record. (This is becoming standard operating procedure in most chain grocery stores, btw.) I care about the environment, but I care about my job more.
The bring your own bags, though... most of them have a loop that slides right over the tab on our plastic holders, so we can make them stay open. That makes them easier and faster than paper, and a lot sturdier than plastic, so we don't have to double bag heavy loads. And it can't be argued that 'bring your own" bags are better for the environment than either paper OR plastic.
My personal opinion is that the stores should stop offering bags at all. Offer the "bring your own" style at checkout for purchase if someone forgets theirs, but have that as the only thing available. 

While I was thinking about this, I also realized there's one other big thing I would change if I could about how most grocery stores do business.  Our local Aldi store has a "deposit" method for carts.  The carts are all chained together, and to unchain them, you must insert a quarter into a little plastic slot, which unlocks the chain on the other end.  You get the quarter back when you return the cart and plug the chain into the slot. I think this is brilliant.  I've been sent out to get carts in snow, ice, slush, lightning, rain, blistering heat, and freezing cold.  Carts are left in parking spaces, where they roll to the far edges of the parking lot, and sometimes clear out onto the street.   With a system such as this, customers would have to return their cart to the store holding area to retrieve their quarter, making my job a lot easier, and probably saving my company a bunch of money in the long run.