Have religious people really thought about whether anyone wants to live forever?
Yes.
Seriously, what will you be doing after the first thousand years, the first million, the first billion, the first googleplex?
I wonder if perhaps we keep going through stages of existence where we don't remember the previous ones but carry forward ingrained personalities, thought processes etc. Evidence for that would be us not remembering the premortal life. Evidence against would be us "having a bright recollection of all our guilt" at the judgement but that doesn't necessarily mean we don't forget later. Also evidence against could be eternal marriage unless we simply happen to know that we are supposed to be together. Perhaps our direct afterlife is still part of this stage of existence and we pass to another at some point in the far future and not remember this one.