Most pros use the appropriate setting for the type of pictures they want to take. That could be A for aperture control, S for shutter control, P for quick grab shots or M for full manual control. It depends on what they are doing and how they want to do it. I would expect a professional to know how to use their camera to best effect in any situation that they are likely to use it in.
A lot of cameras have 2 auto settings - a "green" completely auto and a "P" for Program setting.
If you have both options, try using the "P" for program setting rather than fully auto.
There are a few small but important differences between the 2 settings.
First of all, the "P" setting doesn't usually automatically pop the flash up, whereas the full auto setting does. That means you regain control of when to use flash - and don't look a complete muppet when trying to take pictures of scenery in low light with the flash popped up!
Secondly, the "P" setting usually allows you to adjust the aperture and shutter settings by turning a dial or wheel. That allows you to over-ride the default shutter/aperture combination easily when you want to. You can pick a faster shutter for a fast moving object or a slower one for a ghostly stream. Or you can pick a wide aperture for an out-of-focus background or a small one for maximum depth-of-field.
Third, the "P" setting often turns off auto-ISO, so you learn to set appropriate ISO settings before you go out for the day and update the settings as needed. Letting the camera bump up ISO automatically is not always a good thing!
So using "P" means you can still have the hurried "grab" shot when you need it, but you can also quickly override the settings when you want to. It lets you experiment with the settings without messing up the exposure. It's better than letting the camera go fully-auto because it gives you more flexibility and encourages you to learn how to get more out of your equipment.
If you learn to use the +/- exposure compensation as well as the "P" setting, you will also be able to over-ride when necessary for unusual situations like strong backlighting or excessive reflection. Be careful though - many cameras don't automatically reset the +/- setting when switched off, so you can easily end up compensating when you don't want to!
I use "P", "A" or "S" settings a lot. It's rare that I switch to "M", except when I'm taking pictures for birds in flight, when I don't want the sky to overwhelm the meter and I don't want exposure settings to keep changing.