In my teenage roleplaying group Vampire: The Dark ages was 'my' game. This isn't just because I had bought the books, and most importantly the Book of Storyteller's Secrets for the setting; I had the core book and various supplements for plenty of other games which I either never ran myself, or maybe ran as well as someone else although at different times. Other people had their own games too - where the rest of us were discouraged from buying the supplements, other than maybe player's guides.
More than anything else, though, there was a sense that this world was mine to play with, to know all the secrets of. And I had big plans for it. I had a big bad all worked out; I had his various henchmen, one of whom was the apparent big bad at the end of the first arc of the story, all worked out. I had the skeleton of the overaching story sketched out. I had the first few adventures pretty much written. And I even had a vague plan on tying it in later on to the Transylvanian Chronicles - the campaign White Wolf wrote that could bring Dark Ages characters into the 20th century so you could be badass Elders in the modern game.
Unfortunately, I only ever ran one adventure - over maybe three sessions. Roleplaying is very time consuming, it's true. Even as a teenager, when we were basically gaming every weekday and at least every other weekend, the tally of abandoned campaigns far outnumbered the completed, or even continued ones. It didn't help that we were never a very focused group - constantly starting new games, new campaigns and trying out new systems. It also didn't help that I killed off one of my players in the first adventure, although it was something I couldn't not have done since he was acting so incredibly stupidly - managing to use a special power to make the other players forget he had ever existed. It didn't help either that I'm not a very forceful DM, and ended up happy to slide back into a player role while one of the better DMs in my group took charge.
It was a shame, overall though, that I didn't ever take it any further. I even have all of my notes, filed away still, because I'm that organised when it comes to these things, even though my organisation when it comes to things that matter is completely pisspoor. I ran one other V:DA campaign, which again lasted a single adventure. So much for 'my' game.