I think many people to varying degrees do. And nearly all the population could have such thoughts if they were to be out through enough loss and pain.
But it is a final act for the individual. They will never get to do any of their favourite things again.
It is not a final act for all those left behind. They are left with a life time of hurt, pain and wondering what they could have done. I am going through this for the second time in my life after being the last to see my brother alive and the one to find him dead when I was an adolescent. And have just recently learn my ex partner who I tried so hard to help has done it. Everyone owes it to themselves and all those around them to at least try to live. No one will be happy all the time. If you can't find happiness find meaning in life. With meaning comes the desire to keep going. Accept nothing will be easy and that there is more to a persons life than themselves.