In biopsychology, there is a system in the brain which is called the limbic system. The limbic system is responsible for one's memory, emotions and instincts -drives.
Many researchers suggest that the existence of emotions helped the animal kingdom to respond to sociality and survive better, emotion can also be translated into care and love. These traits also aid why infants, babies and other offsprings of animals are cared for which has a great influence on the survival of the species.
Amygdala, responsible for pain, aggression and grief which is anterior to the hippocampus factors why our memories have incorporated and is strengthened with emotions at that specific circumstance.