In college, my professors taught me a interesting theory for marketing.
They likened it to a ladder and management's goal was to move customer's up the ladder. To gain new customers you will market your less expensive goods and as the relationship progresses, so will the price of the items.
Thus, the customers at the top are your best customers. In theory this sounds good. However, in practice it goes more like this.
Your cable company hikes it rates on you after the first year and the only way to "save" is to add more services and more channels.
Or that affordable rent you used to pay is now sky high because your landlord has raised the rent three years in a row.
Or maybe, that football team you were so loyal to said you need to move to the upper deck because the seats you are currently in will cost $20,000 (in addition to the price of the tickets!) next season.
To some these tactics are merely revenue generators. To others, their best customers are.