Leave them wanting more is the way I look at it. If you give someone everything, you end up feeling like you are doing all the work, they feel smothered, or vice versa, so the relationship breaks down. If you truly want someone in your life and they want to be in yours, you will both work hard at it and be sensitive to the other persons requirements.
As has been said before, don't go comparing relationships, take each on their own merit. We all would like a partner who worships the ground we walk on but that just isn't fair or right. A good relationship involves two equals who are secure enough to know that the other person is with them for a lots of reasons. As soon as one person starts to lose their independence or their ability to think for themselves then it is doomed.
One gf said that I was needy as I wanted a healthy relationship and was willing to work at it, yet she was the one who kept calling when I worked late in the office cos she was all alone. A case of different points of view there!
If only there was a book on this stuff!!