Annoyed with Loblaws

Tell me why? This is not the first time and surely won't be the last.
Alright, so here in Toronto, all stores now charge 5 cents per bag, unless you bring your own environment-friendly bag. Of course, I bring my own.
This morning, while checking out at Loblaws, the cashier proceeded to pile up all my items along the counter's edge, while my three large cloth bags sat in front of the items. I asked her, when paying, if she's going to bag my items? She said to me "oh, I didn't know you wanted them bagged". OH! I guess cloth bags in front of my grocery items on the conveyor belt and her setting them aside means they are just there for decoration.
I told her in quite a snippy tone that I did not realize that all of a sudden I now have to do something that is part of her job mandate. I was so annoyed, that I ended up bagging 50% of the items, as she finally started bagging (nice & slow) after our little "interlude".
I put my bags into the shopping cart and went over to the customer service desk to talk to the store manager I am on very good terms with...her name also happens to be Sylvia!
I asked her, out of curiosity, if I bring my own bags, does that mean I have to bag my own items. She said "no, of course not, the cashier's need to bag your items for you". I told her about what had just happened she apologized on the cashier's behalf and told me she would have a word with her. I have no intention of "getting people into trouble", but I just find it incredibly rude how cashier's more and more think that just because I have my own bag, I should bag the items myself as well.
I'm so annoyed!