After a successful hanging, there are plenty of possible afterlife scenarios where you could have plenty of opportunity for regret. Most religions teach that suicide is punished in the next life. If we're living in a physics experiment or computer simulation, there's no guarantee our consciousness won't be stored elsewhere after death, opening up the possibility of regret, especially of the storage system sucks.

Maybe there won't be an opportunity for regret, but it's certainly not definitive.