I have synesthesia. While it sounds a bit like a disorder, it actually means that I see letters and numbers in color. Like A is red, B is a heathered purple, and C is yellow. 1 is white, 2 is gray, and 3 is green. Synesthesia is often genetic- my mom had it, my sister does as well, but we all vary on the colors we attach to each letter/number.
Each individual letter or number has its own distinct color, but words work differently for me. Generally speaking, a word is colored by its first letter. For instance, K is pink, A is red, T is green, and E is white. But Kate is a pink word. The only exception to this rule is the word "the." It should be green, but it's gray to me. A neutral color. Think of it as the jeans of colored words- yes, they're blue, but they go with everything. "The" is the same way.
I'm not sure if it's because I have synesthesia, but color is a huge deal to me, and I attach great significance to it. It comes majorly into play when I write. All my characters' first and last names have been carefully chosen so they match. Eliza Kane (white/pink), Sawyer Whelan (blue/deep purple), Natalie Addison (green/red), Chris MacGregor (yellow/blue), Amanda Scott (red/blue), Jeff Russell (yellow/red).
Blue is my favorite color of all time, my comfort color, and I tend to gravitate to all things blue. Like the letter S. Or water. One day I made a playlist of all the songs I had in my library that featured water. My aptly titled "Water Music" playlist. I have taken all my book titles from songs on this playlist, and even though the individual titles are not specifically blue (JUST A LITTLE RAIN is yellow, WHERE CURRENTS PULL is purple/blue, ABOVE THE WAVES is red) they all relate back to that color.