Write, speak or mutter, you need to work things through in your mind and get it out of your system. A problem shared is a problem halved is the old saying. But you don’t have to share it with a specific person. You can act like you’re sharing it when writing or speaking. However, you can put the paper in a drawer and never see it anymore. Or speak the words up into space, where no one ever could give chase.
You will feel unburdened. And that is the key. Vent, rant, seethe or simply dispose of your thoughts and you will feel lighter, happier and on the way to a better day already.
Otherwise you are keeping a poison in your system which impacts your mind and health and has little to no impact on any others. Although they may feel an edge or chill from you, it will not eat them up inside.
Just get it out by the end of the day. You will sleep better and be a better person to be around.