I'm not just 'fine'
I'm fine and.....

I'm fine
As in I'm alive
The 'and' is for everything else

I'm fine and...
Sad

Fine and...
Lonely

Fine and...
Scared

Fine and...
Worried

Fine and...
Stressed

Fine and...
Dying

As you can see,
That silent 'and' in
"I'm fine and..."
Is very important