Basically, the more tightly coupled A and B are, the more likely it is that if you change A, you will also have to change B.
Does that help?
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus