I have a simple point and shoot digital camera (Casio Exilm 10.1 megapixels). I take tons of pictures everywhere I go because the camera is small enough to fit into my fanny pack.
I usually don't take time to read the directions for using my photo equipment but prefer to jump right in and learn as I go. I don't recommend this approach, but it's how I tend to operate.
Recently, I decided to experiment with the various choices my camera gives me for light sources. I wondered, "does it really make a difference? Can't I just leave my camera set to Automatic and get the best quality pictures anyway?" Well, let's take a look and find out...
Below are samples of a Gerbera Daisy photographed in my kitchen, at night. My light source is is overhead recessed can lights with fluorescent bulbs designed to simulate natural light. All of the photos are straight out of my camera and have not been altered. The light source settings on my camera are listed below each photo.

1) Camera Setting: Auto WB lighting
(Not too bad. Maybe color is a bit on the pale side.)

2) Camera Setting: Daylight
(This looks too dark.)

3) Camera Setting: Overcast
(Still too dark)

4) Camera Setting: Shade
(Waaay too dark)

5) Camera Setting: Day WHITE Fluorescent
(Not bad though a little washed out.)

6) Camera Setting: Daylight Fluorescent
(Yes! That's pretty accurate for how it looked in person.)

7) Camera Setting: Tungsten Light
(Blek. Way too flat.)
Conclusion:
Photo 1 looks good. The camera was set on Auto for the light source.
But...Photo 6 looks the best. For this photo, I took the time to manually adjust the setting for the proper light source. It looks richer, more colorful and the most accurate representation of what my eye was actually seeing at the time I snapped the picture.
So to answer my question - Yes I can leave my camera on the Auto settings and the photos will look alright. But if I take just a moment longer to look at my light source and manually adjust the camera settings, my photo will look the best. If I decide to alter the photo later in Photoshop - for better color as an example, the end result will still look better because I started with the most accurate light source settings from the start.
Try your own experiment with your camera. A picture is worth a thousand words in the owners manual!