This is obviously extremely minor bad service in the grand scheme of things, but it happens a lot so I'm venting here.
To the very nice baggers at the grocery store:
Yes, I brought my own bags. They're fairly deep, made of canvas. However, I am not Superman. Just because you can manage to fit ALL of my canned goods and heavy bottles in one bag does NOT mean that I will be able to carry it! Please, if you're putting so much heavy stuff in there, stop before it's full! Just because you can doesn't mean you should. I'd rather use a paper bag to carry the excess than injure my arm.
Also, please follow this rule: Once you put the lettuce in the bag, stop putting things in the bag. Do not put things on top of the lettuce unless it's something like another bag of lettuce. A bag of chips? Mostly air, so that's fine. A bag of carrots? A container of yogurt? No. Just - no. I want my lettuce to last more than two days, and being completely squashed does not help with that.
Please, just imagine that YOU are going to have to carry the bags. And eat the food. Use common sense.