In love, you've got very high standards. You know just what you want, even if you're not exactly sure how to get it; and to be sure, your road toward true love could be something of a long one. You need to be courted slowly and carefully, because you don't respond well to the fast, wham-bam approach.
After all, you strive for perfection in yourself as a partner, and you want the same from your lover. When you're committed to someone, you give them your all, and you want that in return. But not everyone is like you. If they're a little less discriminating, it doesn't mean that their love is any less true. But for you, loving someone is all about being in their service -- which can include a healthy dose of criticism and nagging! You consider it your job to worry about the people you love, and to help them lead the best, most refined and high-quality life that they can lead. So, sure, that means you'll nag them a little, if you find them being sloppy around the house or in their pursuit of their career or academic goals. You only do it because you love them, and you want them to be the best person and partner that they can be -- the very same expectations that you put upon yourself.