Are they simply "cold" or "not cold", or does the degree of coldness make a difference? Does it depend on what is being refrigerated?
Your refrigerator should be set so that it maintains a temperature no higher than forty degrees F. This means that you shouldn't be opening the door frequently or leaving it open longer than necessary. If you are aging beef in that refrigerator, you want the temperature to be no more than thirty-five degrees F according to some sources, but these sources conflict.
Below 32 degrees F you are obviously duplicating the functionality of your freezer, but not as well.
Your refrigerator should be cold as possible without having any cold-spots where things will freeze. Inadvertently freezing vegetables or meat really slowly (as is apt to happen in a spot that is just slightly below the freezing point) will damage them in taste and texture.
Proper airflow keeps temperatures more homogenous; you should make sure to allow proper airflow by leaving small gap in the back and sides of fridge. It is not a good idea to cram bags and others in your air space as it will create uneven cooling.