Startitis. It hits us all at one point or another. Some people get frustrated with themselves about it, but why? Let's take a look at the negatives and positives:
Negatives: You end up with a large amount of projects you have to finish. You use up all your needles. You can get easily overwhelmed.
Positives: When you get a new idea, you can act on it and feed your inspiration. You feel more productive. When you get bored or frustrated with one project, you have lots of others to choose from. If one project doesn't work out, you can easily frog it and pick up something else. Having projects at different stages means you still have something to knit if the weather gets too hot for that afghan.
I don't know about you, but I think the pros definitely outweigh the cons. And if you really, really need those needles that are occupied by something else, what else are stitch holders and lifelines for? ;)