I feel like in Eternal Sunshine of the Spotless Mind, the two characters represent repressed parts of each other. Clementine and Joel are very different, but in a way, they complete each other. Clementine was spontaneous, extroverted, impulsive, sensitive, and in touch with her emotions. Joel, on the other hand, was reserved, introverted, calm, and conscious. But they also had similarities.

I believe that their prominent personalities showcased the shadow aspect of the other person, and that is why they were so attracted to each other.

Clementine’s spontaneity and impulsiveness appealed to Joel’s repressed adventurous side, while Joel’s calm and reserved nature appealed to Clementine’s repressed need for stability. Even after they erased each other from their conscious memory, their subconscious minds brought them back together.

You see, humans are all born as whole individuals, but due to some psychosocial conditioning, we have to hide some parts of ourselves. These parts become a part of our shadow self, which is present in our unconscious mind without our conscious awareness.

As humans, we seek to become whole, but instead of integrating with our shadow selves, we choose to be with people who portray our shadow selves. [The Human Magnet Syndrome: Why We Love People Who Hurt Us by Ross Rosenberg]

As time passes, we get fed up with our partners, like how Clementine and Joel couldn’t stand each other at the end of their relationship. It’s because they haven’t accepted their own shadow, and the other person represents it. In the woods when Joel was frustrated and told Clementine that they’re stuck here because of her, and Clementine said, “You know me, I’m impulsive.”  Then Joel claims that’s what he loves about her. This line suggests that Joel is attracted to Clementine’s spontaneity but also finds it frustrating.

No self-acceptance leads to not accepting our partners, and the relationship dies out. This is also explained beautifully by the English poet John Donne in his poem “A Lecture Upon the Shadow.”
When I first saw the movie, I hated Clementine. But then I remembered the quote from Carl Jung, “Everything that irritates us about others can lead us to an understanding of ourselves.”
The second time I watched the movie, I related to Clementine, and I wanted someone else to complete me.

The third time I watched the movie, I realized that Clementine and Joel are parts of myself. One of them represents my conscious self and the other my unconscious self, one my ego and the other my shadow, one my anima and my animus. I realized that I needed to become whole by myself. I needed to integrate my shadow.