Linked lists are one way streets. They have a mailbox (or node, as we call it in computer science), on every block. Every node holds a mystery, a hidden power. It might be information, wisdom, a set of actions, or even an empty statement. These nodes are like us, like people.
When the message comes, if you are the final address, you will understand the instructions. You will read the message about your childhood home, remember that it was green like the outside of an avocado, and you'll make guacamole.
Who sent the message? Maybe your subconscious caught something out the corner of your eye that reminded it of your childhood home. Maybe it got an encrypted message from your gut saying that it needed minerals only avocados can provide. Then maybe your unconscious mind fashioned a provocative message to make sure you bought some avocados and ate them that night.
For a singly linked list, each node gets fed the message with a destination address, but, like the message from our subconscious, there is no 'return to sender' on the envelope. Why take the time to send it back? The message should find what it's looking for. When it does, the node will activate and take care of the rest. The message doesn't need to return to sender. Besides, it would take too long to make its way back to all those other mailboxes and be read by all those nodes.
Some people are really like singly linked lists. They don't ever make it back to their childhood homes. They just remember them sometimes, eat avocados, and go on with their day.
This.next = null;