How do you start designing a game?

[rvalenzuela]

This is not a question asking for help, is more of a question to learn popular opinion.

When you want to design a game from zero, how do you start?

-From the beginning of the story?
-From an event that would be epic to experience in a game?
-From the looks of a character and then create a story around it?
-From a personal experience?

Example: I read somewhere that David Jaffe designed God of War thinking of "Epic Events" and then attached them together through the Story.

I would like to know your answers!