AndrewSwift definitely got to the heart of the matter. I just wanted to share the steps I followed to eliminate ALL song title and "work" problems, and include a couple of little idiosyncrasies....
1) Instead of making a playlist, I went to my library in the "Songs" view, then right clicked the on the column header bar and checked "Work" from the drop-down menu/list. Then, I clicked the "Work" column header to organize the library by work. Now, everything with a work field value was listed together.
2) So, I selected that whole group, and followed steps 2 – 4 in AndrewSwift's instructions --> "OK" => iTunes updated library. All tracks/songs for which the "work" value could be deleted were automatically reorganized to their respective locations.
**Note: the songs stay highlighted during & after editing, as long as you do NOT click on something else. So, I made sure to right-click on one of the highlighted songs and UNCHECK "Use work and movement" before deselecting the list.
3) Those remaining with "work" values were all *.aiff (file format). As has been mentioned [I think], iTunes does not change the "work" field for *.aiff.
4) So, I just selected all the *.aiff songs --> File > Convert > Create Apple Lossless Version.
...took a shower and let it run (I had a LOT of *.aiff songs). When I came back, I deleted all the highlighted *.aiff from my library.
5) Then, I used AndrewSwift's instructions to delete all the work values from my new Apple Lossless (*.alac) tracks.
6) Sync'd iPhone, and Music library was repopulated by *.alac WITHOUT those stupid "work" values replacing the song titles. PLUS, it freed up some more space on my phone.
...pretty darned easy 🙂
Edit to add: in the interest of full disclosure, I should mention that I didn't actually delete all my *.aiff. I told iTunes to send them to the Trash, then copied them from the trash to a folder that ended up on an external drive.