The thing that drives me forward in a story is the plot. I love a good one and I'm always thinking up new ones. Sometimes they comes from characters sometimes they don't.
For example, my favorite wizard, Brashani, decides to clean up the ruined city of Marngol, which was destroyed in an invasion when he was a young man. Since the city was home to many wizards, I figured that there must be many different things lurked in the home's of the wizards, good and bad (mostly bad for plot reasons). So stories about the clean up effort focus on what he finds and how he deals with it. So some of the stories are more mystery (he finds a baby in a tower; he follows clues to a treasure) or straight conflict (the ghosts of the slain wizards are angry with him, he tries to accommodate them but it is not enough and they clash).
Notice in all cases, the stories derive from Brashani's motivation to clean up the town. These are character driven. Other stories are not. For example, the characters find themselves in circumstances beyond their control. They try to correct or influence the situation but cannot. Or they can, but it is really hard and they risk dying.
In such a story, the plot is is center stage. The characters and the personal ambitions are irrelevant. They have motivation -- to stop or change the circumstances around them -- but other goals, like getting a promotion, or writing a great novel are, for the purposes of the story, out the window. They might be mentioned in passing to flavor the characters but no development of these goals is possible because the circumstances they find themselves in keep intruding.
Example: Bobby wants to write a novel but there are too many distractions and interruptions in his life to make that feasible. There is work or school. A constant barrage of email, IMs, and online chats to deal with. If Bobby is a college student, say, then there is also his coursework to focus on, studying. In fact if he's studying to be a lawyer, he must immerse himself in his courses and study groups or risk washing out the first year. He still wants to write but his wants other things too. And, of course, he needs time for a social life too.
These days character-driven plot seems to be preferred because when the plot is driven by characters and their actions we can identify with them and root for them and that makes the story far more enjoyable for the reader.
So if you find yourself in a plot that is not character driven stop and look at your characters. Make sure they have reasons to do what they are doing. If not, change characters. If they do, follow them and let them guide the story to see where is goes. You might be surprised what you find.