That's a very emotionally charged description of sleep training @angelpie33 .
We sleep trained our son as he was taking over an hour to fall asleep. Cosleeping, rocking, holding, absolutely nothing was working, we were overstimulating him loads. We decided to do Ferber i.e. put him down and check in on him every few minutes. He cried in total for 20 minutes. The next 2 nights for 2 minutes, I didn't even get to go in to check on him first. The fourth night I put him down and he cood and babbled and rolled over and went to sleep. Same for naps. I put him down, there was some crying on day 1.
But even to this day, he sometimes wakes in the middle of the night, looks at the monitor, does some rolls, gets up, sits back down, babbles a bit and goes back to sleep.
Sometimes he cries and I go in right away as I know that he now only cries because something is wrong/ he wants a boob.
I myself need complete silence and darkness to fall asleep so I guess he might be the same.
Every baby really is different. You may think 20 minutes of crying is a lot but he was much happier after that. But I do know many babies' personality would not lend itself well to this. If my baby had been happy cosleeping, I'd be doing that still.
And in real life, most of my friends have done some kind of sleep training. Many people cannot cope with 60 minutes of sleep at a time for 12 months +