Black and White images (b/n) are based by the absence of color. Just black and white. But in all pictures, we will discover a huge variety of grey tones. In digital formats, the picture is taken with color and processed in b/n.
B/N images are meant to be good when they obey the zone system. Briefly, this system consists on getting all grey tones, including the purest white and the darkest black. This technique was created by American photographer Ansel Adams (USA 1902-1984).
Nowadays, all image processing programs allow the user control the grey scale by the histogram. But sometimes, a picture becomes beautiful without following the correct parameters, just being made as our own choice.
Personally, I do like b/n because it remembers me the old times. Also, I think I can see more about people and their expressions. For example, taking pictures of kids makes me see how small they are or how mature they are becoming.