Mine is from a manga series by
Tatsuki Fujimoto (also known for Chainsaw Man)
It's deeply related to suicide in my opinion.
It's the most mindfucking piece of fiction I ever read but it has such a brilliant meaning.
Basically, we are all playing a role.
We are lying to ourselves, and that's what keeps us alive.
We don't exist for a bigger meaning.
Not for the sake of a god, the sake of love, for happiness or the sake of humanity...
Those reasons prevent us to think life is actually
meaningless and
absurd.
No, we are just dictated by desires. And those are replaceable, shallow and once satisfied they ask for more.
Your first love isn't the person you will marry and die with.
You could argue that a couple like this existed but then if you imagine a life where they didn't meet, they would have live and fall in love with someone else.
You could think it's an exemple out of nowhere but it's actually related to Fire Punch while being extremely simplified.
I could go for hours explaining how deep Fire Punch is but it would be boring and you wouldn't even understand how it is related to a story about a fist on fire !
If you happen to read a short synopsis I'm definitely sure you'll be interested ;)