Auto mode has its place. Firstly when you are starting out, trying to learn all the features of your camera at once is stupid. Start on Auto, learn where the buttons are, get a good feel for the camera, and then if you want start looking at ISO, Shutter Speed, Aperture. Try to learn one at a time by using semi-auto modes.

Many years ago a wise man (not that long ago and not one of those wise men, how old do you thing I am ) also told me when you finish your shoot, put your camera on Auto before heading home, or putting it away.

His reasoning, you are driving home and suddenly a yeti crosses the road in front of you, you grab the camera, and snap a shot off..but you have left it on manual from your waterfall shoot and the shutter speed is set to 10 seconds. Nice blurry mess of a shot and not an identifiable yeti in it anywhere. At least if you put it back on Auto when you finished your shoot, you would have a reasonable chance of getting something that proves you saw a yeti (or some guy taking a short cut to a fancy dress party).