I know this has been a thing for years but like why

Was scrolling tumblr and I saw a post like "Caseoh headcanons !!!" and no hate but why are we headcanoning real life grown ass human beings? Like how do you headcanon irl people it just doesn't make sense. "Grown woman headcanon she cries herself to sleep" Like you may be right but what.

Anyways if anybody has any headcanons for me let me know I'll tell you whether its canon or not.