You exist. No terms and conditions apply.  There’s no manual, just a stern nod towards personal responsibility and the freedom (read: mild terror) of choice. That's Existentialism in a nutshell, and it’s certainly not for everyone.

Thinkers like Søren Kierkegaard, Friedrich Nietzsche, Jean-Paul Sartre and Martin Heidegger mused about this, probably while debating over black coffee in dimly lit cafés or having existential crises on park benches. Their consensus? Existence comes before essence, meaning you exist first and then define your purpose. Or, to put it another way, life's like an unsolicited improv session – no script, just a stage and a spotlight.  

Through their writings, these philosophers challenge us to live authentically, face the absurdity of existence and make choices that define our very being.