The search for perfection in terms of Kafka's The Hunger Artist means the inability to accept reality for what it is. The Hunger Artist is always dissatisfied and feels misunderstood. He never feels satisfaction or joy. He has professional success, but no meaning. It's very symbolic that he gives up food to find meaning, but it is never enough. He never finds solace in his own actions. This is ultimately the "search for perfection"; nothing one does is ever enough.
Food and passion are equated in the story. Notice that the panther who has an enormous appetite which shows his joy in life and his passion, can act in accordance with nature but the artist cannot. He is stifled.
Kafka is saying the man or woman who is searching for perfection, is not really living life. It is as if they are "waiting" on the peripheral, not allowing themselves to feel acceptance and joy or passion.