One problem many developing writers have is that readers don't like their
main characters and don't care what happens to them. If you can get readers
to become emotionally invested in your protagonist, then they'll follow you
almost anywhere.
Readers tend to like characters who are struggling to achieve a goal. This
simple principle can be invaluable in creating sympathetic protagonists.
Characters working toward a goal are active characters. Characters who
aren't working toward a goal are reactive. Reactive characters are much
weaker than active characters, and we tend not to like them. Unfortunately,
many writers end up unknowingly creating reactive protagonists.
Here's a scene with one active character and one reactive character:
Joe: "What do you want to do tonight?"
Jane: "I don't know."
Joe: "Let's go see Lord of the Rings."
Jane: "I already saw it."
Joe: "Well, let's go bowling then."
Jane: "I hate bowling."
Joe: "We could rent a video and stay home."
Jane: "We did that last night."
Joe is the active character, Jane reactive. Joe is working toward a goal
(finding something pleasant for them to do together). Jane is just reacting
to what Joe says, and is seemingly not interested in achieving that goal or
any other. We relate to Joe, because at least he's trying. We dislike
Jane, because she's not trying.
Some people certainly are reactive, and it's fine to have reactive
characters in your story. Just be aware that's what you're doing, and don't
expect your readers to like those characters.