What is the reason for this kind of error while deleting a record in salesforce?

This is generic error message prompted by Salesforce many times, which is not well informative. To get informative message, we can try to delete same record in “Developer Console”. In Developer Console Debug log, we will get exact error message.
Example : Lets say there is one record which is parent of more than 2000 records and grand parent of 5000 records. In such scenario from developer console it gives error something like “record cannot be deleted because it has many associated objects” However in User Interface, it will just display that “Object cannot be deleted”.