I don't like the part about "no circular dependencies." If the language supports it, such as in c#, then why not? There are cases where you want Class A to use

I don't like the part about "no circular dependencies." If the language supports it, such as in c#, then why not? There are cases where you want Class A to use a B and Class B to use an A. Unless that's not the kind that they're talking about.