CouplersAll the smells in this group contribute to excessive coupling between
classes or show what happens if coupling is replaced by excessive
delegation.Feature Envy
A method accesses the data of another object more than its own data.Inappropriate Intimacy
One class uses the internal fields and methods of another class.Message Chains
In code you see a series of calls resembling $a->b()->c()->d()Middle Man
If a class performs only one action, delegating work to another class,
why does it exist at all?