The song "Was Only" specifically explores the idea that Stevens' memories of his mother are tainted or biased due to the limitations of his perspective. He reflects on the incomplete and flawed understanding of her as a person during her life and grapples with the idea that he may have missed out on truly knowing her.
Here are a few lines from the song that capture this sentiment:
"I could only see what was in front of me
I could only be who I was"
"Your secrets were safe in my hands
I kept you safe in my thoughts
But now they're all washed away"
In the chorus, Stevens repeats the line "I remember everything", expressing both the intensity of his memories and his inability to fully comprehend their entirety.
Ultimately, "Was Only" is a song of regret, longing, and unresolved emotions as Stevens grapples with his mother's absence and the gaps in his understanding of her.