The Case of the Missing Peanuts

I don't get it. I can do those logic puzzles and figure out the missing information with a few clues. I can work Sudoku puzzles in fast time. I cannot, however, manage to find my shopping cart when I am at the market.
Someone went home with MY peanuts! It must be so, because the peanuts never came home with me. I selected a nice fresh package of salted peanuts in the shell and put them into my cart. (Well, I thought it was my cart.)
I got home and unloaded the groceries, still not realizing the peanuts were missing. A few days later, I got a craving for peanuts and remembered I had never unloaded them. Dummy! I knew instantly what had happened. I do this kind of thing all the time. So what's the matter with me anyway?
I am so focused on checking off the items on my list and doing it in a hurry so I don't have be exposed to the piped-in music for too long that I either take someone else's cart or I certainly load up their cart then drive off with my own.
I hope they are enjoying their peanuts! I have to wait for two weeks before we go back to the market. (sigh)
I need a personal shopper for more reasons than this!