For me, one danger sign when writing a manuscript is if I'm waiting to get to the good part. "Can't wait to write that scene! Have to build up to it," I think. This can result in filler: boring scenes that are just marking time.
Now, this is not a danger sign for outliners. Since outliners know exactly what's going to happen and when, their build-up scenes don't just kill time or delay the inevitable. And any writer can look forward to a book's payoff--the big battle, the point where the lovers finally reunite, etc.--without having that anticipation signal danger.
But I'm not an outliner, and often when I'm holding off on "the good part," I find that the best thing I can do is go ahead and write that good part, and then figure out what's next. If two characters are going to kiss, I don't put them in scene after scene after scene where they almost kiss. There are plenty of writers who can make that kind of suspense work. Not me. I may delay the kiss a bit, but once I know they're going to kiss, I'd rather have them lock lips already--and then figure out what happens next.
I always want to get to the part I don't know. I'm the same way as a reader. Once I figure something out, I don't want to wait too long for the main character to catch up with me.
Pacing is a balancing act--not rushing, not dragging things out.