While design patterns are undoubtedly a useful tool, many prominent computer scientists have expressed criticism directed both at the Design Patterns: Elements of Reusable Object-Oriented Software book and at the general way patterns are used in practice.
Over the years, programmers have learned that the patterns in the GoF book really aren't as widely applicable as the authors thought. Lots of them only apply to the object-oriented world. If we try to use them with a functional language, they are largely useless. They can also be greatly simplified when used in aspect-oriented languages.
Delphi, however, is an object-oriented language, so we can reuse most of the Gang of Four observations. Still, it is important to keep in mind how patterns should be used in practice.
As a main rule, you should never use design patterns to architect the software. Design patterns...