Here is a great description of what shopping with little kids is like. I only had four with me at that stage, but I can sympathize! It is amazing how much stuff can find its way into the shopping cart without your knowledge. One of the delights of having kids grow up is that eventually they are old enough so that you can leave them at home while you go shopping by yourself. Even better is when they are old enough to go grocery shopping for you - although then the unapproved-item count goes back up, since they take advantage of the task to stock up on energy drinks, chips, and junk food. That is, in fact, the bait that convinces them to spend an hour at the grocery store buying detergents, bread, and toilet paper.
Of course, having a husband along is an even more effective way to fill up the cart with things you don't have on your list. I remember a shopping trip years ago with my dad to get three things my mom needed; we ended up with an entire grocery cart full of exotic things my mom had to deal with, like a watermelon and a pineapple and all kinds of odd cookies and condiments. My husband has learned to deputize our youngest son to get Oreos on every trip, so he doesn't even have to go to increase the grocery bill.