I was going to be dropping my son off at daycare before work (something I usually didn’t do), and my normal routine was to stop at Wawa for breakfast. I stopped, got out, grabbed my breakfast, got back in, and only then remembered that he was in the back. He had been VERY uncharacteristically quiet prior, and I was tired, and I just… forgot he was in the back.
It caused absolutely no harm (I was only in the Wawa for 5-10 min), but it was a very sobering moment. I can definitely understand how it happens.