What are basic emotions?
Basic emotions are reasonable, healthy responses to real events. In one sense, they are "pure."

Someone you love dies. Your sadness in response to the real loss is a healthy part of the grieving process.

Your child carelessly breaks a family heirloom. Both your anger and your sadness reveal the importance of the loss and the frustration with the recklessness that was responsible for it.

A sound from the basement wakes you up suddenly in the middle of the night. The fear you feel makes you cautious while the anger mobilizes you to resist the threat if necessary. Both emotions trigger the release of adrenaline that makes you suddenly alert.