Build first or talk to users first? What's your process?

Hey everyone, I'm kind of stuck on something and would love to get your thoughts.

What's your usual process?

Do you typically go out and talk to people on social media to see if there's a real need for something before you start building a product?

Or do you build the product first and then go looking for users?

I'm feeling a bit lost in this 'chicken or the egg' situation right now.