Spoilers
“Musings of a Cigarette Smoking Man”

“Life is like a box of chocolates. A cheap, thoughtless, perfunctory gift that nobody ever asks for. Unreturnable because all you get back is another box of chocolates. So you’re stuck with this undefinable whipped mint crap that you mindlessly wolf down when there’s nothing else left to eat. Sure, once in a while there’s a peanut butter cup or an English toffee. But they’re gone too fast and the taste is… fleeting. So, you end up with nothing but broken bits filled with hardened jelly and teeth-shattering nuts. And if you’re desperate enough to eat those, all you got left is an empty box filled with useless brown paper wrappers“
This monologue came from the season four, episode seven of the X-Files, out of the mouth of the Cigarette Smoking Man, and I loved it. It was not the kind of monologue one expected, taking a famous quote from Forest Gump and warping it into a view of life considerably more negative.

The episode featured a telling of the back story of CSM, played by William B. Davis (and a younger version played by Chris Owens). In the show, CSM is given credit (or blamed depending on how you look at it) for the assassination of JFK and Martin Luthor King Jr, as well as many other historical moments. However, it is implied that the story may or may not be accurate, as Lone Gunman Frohike stated that he found this story in an old magazine of his.
This article is a fictional tale written by CSM himself, though, as he said, the ending had been changed. Exactly what was changed was not included keeping us uncertain about the accuracy of the episode.
I liked the way they leave it uncertain as it felt sort of doubtful that one man could be behind all of the things CSM was given credit for.

The main purpose of the episode is to show just how dangerous Cigarette Smoking Man was and continue to set him up as the big bad for the series, while potentially humanizing the character a touch. Imagine the pain and death that could have been spared had the magazine just published the story he wrote as he had intended it.
The episode also gives the actual cigarettes as a symbol for the evil that CSM does, as he was preparing to resign, he crumpled up the cigarette pack and once he realized that his life was not changing, he purchased a new pack right away.
I had always wanted CSM to be killed by Mulder, multiple times over the series so far. This provides even more context to the villain.