Social Dilemma-Did I Do Something Wrong in the Market Express Lane?

Okay, yesterday afternoon, inbetween the raindrops, I went over to Walmart to pick up some last minute items because I'm leaving on vacation on Saturday.  After I had picked up what I needed which included two towels, deodorant, and 30 cans of Fancy Feast Cat Food.  I went to the Express aisle.  Now yes, technically I had more than 20 items in the Express lane, but hear me out.  I had bought ten cans each of three different flavors of food. So when I put them on the counter to be checked out. I piled them up on top of each other.  Ten, ten and ten.  Then I told the cashier, there's ten of these so she only had to scan one can and throw the others in the bag.  Same with the next flavor, etc.  Still there was someone behind me who was giving me every kind of passive aggressive sigh they possibly could.   I paid for my stuff and I waited for the woman behind me to check out.  She had about 18 separate items.   At the end of her checking out, I asked the cashier, who took longer to check out, me or that woman.  She said the other woman.  I asked the cashier if she minded what I did.  She said no because I had it all set so that only one of each flavor of cat food had to be checked out.   But the woman was furious.  So I ask you, do you think I did the wrong thing?  Should I have stayed out of the Express Lane, or was I okay to go in that lane.  Let me know what you think on the 98-3 TRY Facebook page.