For purpose of discussion, assume that due to bad luck, this asteroid has evaded the detection of all amateur and professional astronomers until about six months from impact. The asteroid is too large to deflect with humanity's current spacefaring capabilities, and the general scientific consensus is that the impact will end all multicellular life on Earth.
What do those six months look like?
I don't know why but this really speaks to me as realistic.
There'll be whole ass cults of people who think they are vaporization proof because they're just built different, denying all mortality right until the end
Some people wanna grift money until there is no more civilization for the money