Oversimplification
When creating a product aimed at gamers, you cannot lump strategy gamers, role-playing gamers and those who kill time on the bus playing on their phones together. If we define all these people as a homogeneous group of customers, we greatly overestimate the potential sales of a specific product aimed at meeting the needs of only one of these groups.
Too many market segments
If you have identified up to 20 groups of people interested in your product, it is likely that not all of them are of equal importance. Not all of the segments you identify will be of the same size, and customer value will also vary between different buyer groups. It is worth focusing only on those target groups where the return on your efforts will be greater than the cost of implementation.
Inappropriate segmentation criteria
There are times when a company chooses incorrect segmentation criteria, with the result that cannot contribute much to the company's activities.
No customization
Segmentation carried out by a company is not just a matter of writing it down on a piece of paper. The division carried out is a tool whose full use requires adapting the company's strategy to the results obtained. If a manager knows that it is not possible to identify the most important group of clients and that his potential clients are divided into 2 equally important groups, he should not devote all his efforts to a single segment of clients in particular.