What you may call a Perfect Life requires a unified, coherent and harmonious approach to living. It requires Perfect Unity at three most important levels of human existence -- here and in the hereafter.
And that means when you become a Muslim -- no matter how that happens, whether by birth or by conversion -- you acquire three kinds of Unity.
Or you must.
Cognitive or Conceptual Unity;
Affective or Emotional Unity;
Behavioral or Operational Unity.
Cognitive is how you acquire and structure your knowledge and your thought.
Affective is how you generate and manage your emotions and feelings.
Behavioral is how you act and do things in this world on a day-to-day basis.
Laa Ilaaha Illallah provides the perfect organizing principle for the first two.
Muhammad Rasulullah, in addition, provides the framework for everyday practical life.
Taken together, Laa Ilaaha Illallah, Muhammad Rasulullah provides a formula for living a life of perfect Cognitive-Affective-Behavioral harmony, richness and success in this world as well as in the next.