Giving one child better treatment than others
It appears in Bukhaari Shareef [1] that a sahaabi by the name of Nu`maan bin Basheer radiallahu anhu had presented a slave to his son. His wife insisted that she would only be pleased with him until Nabi salallahu alayhi wasallam approved of him presenting the slave to his son.
This sahaabi went up to Nabi salallahu alayhi wasallam and related what had transpired between him and his wife. He then requested Nabi salallahu alayhi wasallam to approve of his gift to his son.