Is blood thicker than water?

Over the past two years I have thought about this phrase over and over and over. The expression, meaning that family bonds are closer than those of outsiders. In any situation where one was deciding to go with family or "fill in the blank" a person would always side with his family. Now I know that certain crazy situations it is necessary to break ties with your family but those situations are few and far between. So the saying sticks: Blood is thicker than water...or is it? In all situations, to make a right decision one would have to know what the water is and of course what was done to make the blood "thin". In this case, the water is a church and the "blood thinning" is "going to the movies" and "listening to bad kinds of music". I cant really say much more because I am not here to talk down on anybody or anything but the saying keeps ringing in my head... and in this situation, water was found to be much thicker than blood!