My mom is like that, where she has a stare down with the cash register to make sure that not one thing is overpriced, or that the cashier doesn't swipe something more than once. But I don't usually pay attention. And honestly, there have been times where I was charged for two things when I only got one, and I didn't go back cause I didn't really care at the time. (They were not expensive things, maybe 5 bucks each).
I definitely didn't STEAL them. Stealing is purposely taking something. I didn't do anything like that, it was the cashiers mistake for not scanning all three items. And I just realized it when I check the receipt (And the only reason I checked the receipt is because my mom had called to ask me what the total was so she could deduct it). If I had bought it with my own money, I would have rolled the receipt up without looking at it and thrown it away.