The manager/baggers need to keep their comments to themselves = good customer service.
The reason why they don't like to deal with the bags is the difference in sizes. With the standard plastic grocery bag or paper grocery bag, the bagger can fill them very quickly, knows just what will fit in, etc. Having to slow down with bagging items is a big NO NO in most grocery stores--baggers are expected to be speedy by their managers--same as the cashier.