When you purchase an existing business why is it important to know the owners reason for selling?

In purchasing an existing business, it is important to know the owner's reason for selling his or her business, because the business may be unprofitable or under-performing, which is why they are selling it or maybe they have a succeeding debt to one of their investors in their business. But, there are also some advantages in buying existing businesses, you get to acquire current customers, inventories, contacts, staff and suppliers.