Our mind is like the motherboard of a computer; we can store and retrieve anything at any time. As you experience the world, you create pathways of events that you have travelled.
Some trips you have shown interest. Where as others you had to learn from your mistake. For some, they have memories that have been repressed and are only retrieved by a trigger. This would be our long-term memory drive.
What about our short term memory, how good are you at remembering what you ate yesterday for lunch? Or, the last thing that you finish reading?
I can say that my short term memory sucks! It is probably since there is a lack of emotions. I can not count how many times I walked into a different room only to forget why I was heading in that direction.
Emotions and our memory play a massive part in our perception of others and the world. It also can help with problem-solving skills. Humans are not the only species to connect emotions and memories. Look into the eyes of an animal; you will be able to tell how they are feeling. If the bond is strong, that animal will remember you.