I was running out space on the drive where I stored my iTunes media, because every time I opened iTunes, the application would immediately begin downloading TV shows I had purchased on my Apple TV.
How can you stop iTunes from downloading purchased TV shows whenever you open it?
See my answer below
Note: Though it may or may not be entirely relevant to the problem (this bug has bit me across versions of iTunes and OS X), the bug was reproduced and eradicated using iTunes 11.1.3 under Mac OS X 10.9 Mavericks
Possibly related detail: I write possibly, because I've modified where my iTunes media lives outside of the iTunes defaults.
This is a common thing to do, when you realize the space on the meager 128 GB drive that came with your computer will no longer suffice.
This detail also warrants mentioning, because the use case deviates slightly from the norm, and pathing often emerges as the culprit in software-related bugs.
Another possibly related detail: I've moved the location of my iTunes media a couple of times, but didn't delete the old location's directory, which is also a parent directory of my current iTunes media location. I've been meaning to re-organize, but there were music files I didn't want to lose at the time I made to the decision to change the media location a second time.
I mention this, because as a software engineer I've run into stupid bugs and relative vs. absolute path issues simply because a user chose to nest directories awkwardly or carelessly.