You have confused desire with attachment. In your defense, this confusion also appears in some interpretations of Theravada Buddhism. But in Vajrayana Buddhism, you don’t try to eliminate feelings or desire. You just don’t become attached or averse to them. When you are happy, you let yourself be happy, until you aren’t. When you are sad, you let yourself be sad, until you aren’t. That’s not always easy, but If you do certain spiritual practices, you can learn to more effectively roll with whatever punches the universe throws at you.