Over time I found the cat becoming somewhat surly and bothersome. As I analyzed the problem it occurred to me that I spent almost no time focused solely on the cat. In an experiment I began spending 6 periods a day of 30 seconds each focused totally on the cat. Within two weeks the cat returned to being friendly and playful. Couples who have used this technique with each other have consistently reported the same phenomenon.
Friendship takes time and effort.
When a friendship is going well the effort often goes unnoticed. But it is effort none the less. We greet friends when they arrive, listen to their stories, celebrate their successes and empathize with their pains. When a friend is in need we will often drop everything and become fully available. The same efforts that work in friendships can and will work in a primary relationship.