Four letters and a river of definitions

A word that has different meanings to each of us,
A word with a meaning that goes deeper than the ocean
Carved into four letters,
L I F E
A word that evokes emotions
Lessons we didn't study for, yet got tested
The contrast between brutality and tenderness
It is hard to decide whether I love or hate this life.
My love for it stems from all the experiences I've had
Or would I rather hate it for all the experiences I had?
It is never a fixed choice