We haven’t done any version of this exercise in a while; I believe it’s time to do it again.
With the idea in mind that you’re going to completely destroy whatever you write anyway, take out a few loose pieces of paper (read: not in your usual journal or whatever) and write with absolute freedom about anything you might be censoring yourself about because it’s awkward, complicated or embarrassing to write about and you would definitely feel some kind of way about it if anyone else read it. Let frustration rip about your spouse! Rant about an unpopular political opinion! Detail your kink! Confess to doing crimes! Carry on in detail about your secret ambition! Whatever!
Writing with the intention of destroying your words when you’ve finished could lead you to some fascinating places of truth and catharsis.
If you want to actually destroy your writing at the end, have at it. If you want to keep it, that’s cool, too. What you did, though, was trick your brain into removing your inner “what if someone sees this” judgment and let you get these deep things on paper. There’s power in that. Repeat as needed.