Well, I could have gone into more detail I suppose.
There's no reason at all for us to suspect that there is such a thing as a soul. There is no reason to suspect that there are fairies, leprechauns, Allah or pixies either.
Some people do not like the thought that once they die there is nothing afterwards, so they invent the idea of souls and afterlives to make themselves feel better. It's the same concept as to why people believe in god.
There's nothing bad personally about dying, since once you are dead, you don't know that you are dead, so there is nothing to feel bad about. A person's death only adversely affects the people they leave behind who will mourn them.
Since a person's self-awareness and feelings are made possible by the presence of a brain and all the chemical reactions that entails within that brain, it is reasonable to suspect that once that brain is dead, that person no longer has any ability to be self aware or to have feelings.
As I see it, there are three kinds of death: biological death (when the body and brain are dead and there is no electro-chemical activity within), genetic death (when there are no more living decendants of an individual left and hence the genes passed on by the individual have disappeared along that genetic line) and memory death (when the dead individual has been forgotten by everyone alive).
We will all undergo biological death. Some of us will undergo genetic death. Almost all of us will undergo memory death.
But, since we will not be alive to witness these things, it doesn't matter one bit, regardless of any opnion otherwise. How can it matter to an individual if that individual is not alive to be able to regret it?