What does Nick metaphorically compare us to in the closing lines of The Great Gatsby?please help asap. (: thanks so much!

Metaphorically, Nick compares us to boats that beat on,
pressing on against the currents that can be rough at times. Nick believes we are often
stuck in the past because the currents hold our boats from going forward into the
future. Nick believes that Gatsby lived in the past and could not be free to move
forward into the future. Daisy kept Gatsby held in the past. He could not get over
loving the Daisy he once knew. Nick realized that Daisy had changed, but Gatsby
continues to love Daisy. Gatsby died living in the past. His boat beat against the
current and was pulled back into the past. He dies loving
Daisy:

So we
beat on, boats against the current, borne back ceaselessly into the
past.