Wait out your bad days, bad months and bad years. Don’t think deeper than the random thoughts of everyday. Imagine you’re all good. Not good, perfect.
By the time one has a middle age crisis, you’ll be a solid human being with no doubts whatsoever, full of certainty, predictable and serene.
You shall know thyself the easy way: the shell molded by all the things you never thought about, guarding your soul from your own prying eyes.
You have reached the maximum level of privacy settings available on planet Earth: knowing thyself without a clue about who you are. One caveat: you might want to consider that knowing the universe might be interesting though …