I'd like to make it so my writers, authors and journalist actually enjoy writing! I'm tired of them getting stressed out so quickly by writing. when IMO it should be fun. Personally I usually enjoy writing and it rarely stresses me out. Though I suppose it would depend on what I was writing or why I was writing. Either way, I want my sims who have writing careers and Journalism careers to not get so stressed writing. I searched though several things in Retuner. I looked under "writing" but I don't see anything in regards to mood decay or fun factors. Anyone know where I should look?

I don't think it's possible to do that with Retuner. With Retuner you can change advertised outputs (i.e. motive changes) like Fun in order to interest or disinterest sims from an activity. But AFAIK to modify the actual fun (or any motive) that a sim receives from doing the activity requires a tuning mod. It's not too difficult to do and only requires some basic knowledge of S3PE. There are some tutorials about making basic ITUN mods linked on this site, including this one which is how I learned how to do it. You could also look on MTS and simsasylum to see if anyone has already made a 'writing is fun' type mod. I have a mod someone made to make street art slightly fun. There might be something similar for writing.

Do you have the Multitab 6000 from the Store? That's what I use to quickly fill a sim's fun bar. The 'Play Social Games' interaction is one of the the quickest ways to max the fun bar and you can queue it up while the sim is setting at the desk, cancel writing, then queue the sim up to continue the novel right after they are done on the multitab. That's how I manage my sims who write a lot. Also, the Carefree LTR increases fun 25% faster, which can be useful for such sims. Also, the multitab make doing homework fun. I give one to all my child sims.