Shades of Yellow

It starts in the morning
When everything's fresh
It jumps in the evening
When anything's crushed

If its the same color
Then why does it change?
From a sunflower yellow
To a diluted watery red?

The answer is a riddle
Just like the rest
That will never be answered
Because I'm too afraid

But perhaps you can answer it
Because I never will
A mediocre answer that is never complete
Because the question is caged away

But is still very yellow
Like a sitting tea kettle
But it is not quite that bright
But it is still yellow