They asked people who survived jumping from the Golden Gate Bridge what they were thinking on the way down. They all said they felt instant regret the moment they let go of the rail.
I do wonder what the story would be if we could somehow ask the people who didn't survive. Likely a purely philosophical question with no answer, but I wonder how many of the people who do end their own lives don't regret it at all.
Most likely the dead are not capable of regret, but if there is some manner of afterlife where people can contemplate their actions, I do wonder how many of them would regret their suicides
If there was more focus on screening for impulsive thoughts and disrupting people who suddenly change behaviour, modern suicide prevention would do much better. The people who really want to die do not engage with therapy or mental health services because they know they'll be having their freedom taken away if they mention their thoughts to anyone else. That's why many of these stories go like "oh he looked so happy! no one could have known" - yeah because he was smart enough not to say anything;)
Edit: Implied is that how determined they were to commit suicide influenced their behavior before survival/death was fully out of their control.