Ensuring long-term and productive customer relationships is very important for the continuity of business. Interestingly, customer relationships are always forged between people, even in the context of doing business. Especially in relationship selling, where the aim is to maintain productive and long-term customer relationships, it is extremely important to understand how customer relationships develop between people. So far, earlier studies have not been able to explain why and by which mechanism some customer relationships deepen, while others don't.