What you see is not always what you get on your photograph.
We saw how light can appear differently in photographs, compared to our eyes.
The contrast is always higher in photographs.
That is, shadows are always darker on photographs than they are when looking with our eyes.
Do an experiment.
1) Photograph a still life with a bright light to one side.
2) Take a second picture after you've placed a reflector (piece of white cardboard, newspaper, etc.) on the side of the still life opposite from the light.
Reflect the light from your light back onto the still life.
The shadows will appear brighter by using the reflector.
3) Compare the still life with your two photographs of the still life.
The photograph with the reflector will be more similar to the way the still life looks with your eyes.
As described, shadows are always darker in photographs.
This increase in contrast can be beneficial or detrimental.
For example, when you want to emphasize the weathered face of a veteran lobster fisherman, the shadows created by sidelighting will be good.
The increase in contrast will be detrimental if you're photographing a baseball team on a sunny day.
You won't be able to see the eyes of the players in the dark shadows created by their hats.
Use fill-in flash.