The Psychology of Marketing

Finally, there are practical factors that enter into marketing. If it is simply inconvenient for a customer to purchase from you or you simply cannot satisfy their needs with the product they are seeking, then don't attempt to fit a square peg into a round hole. Too many sales are lost by trying to do so. More importantly, you may risk ending a future relationship with the customer by losing their trust.

In the end you want to sell customers by gaining their trust and building a relationship based on customer satisfaction and by being honest and not trying to be everything to everyone.