I'll take the bait.
The first time I drove to church with all three of my kids including my then newborn son, the older two got out of the passenger side of the car like they do every week and I took two steps towards the door of the church from my car before I realized I forgot about my son.
The issue was it was a change of routine. It was March so even if I left him he would have been fine, but even that single moment of "forgetting" him makes me feel uneasy to this day. I'm kind of a forgetful person, which makes it worse.
All that said, it literally was just a couple seconds. I don't see how you forget for a few minutes much less an entire freaking day. There was a dude who did that at one of my clients down in Texas. He never took his kid to daycare, so the change in schedule (having to take his kid to daycare rather than work), caused it to slip his mind. Wife divorced him, life fell apart, etc. I can't say it's not deserved.