It is agreed that design patterns can solve complexities and problems in software design phases, but improper applicability of Design Patterns can lead to bad designs that can facilitate software design errors.  Be very careful when using or applying design patterns.  Do not use a pattern to solve a problem that does not need it.  Do not simply ornament software design using a design pattern when it is not at all required in that context.  Think twice before you decide to use them in your design.  Understand the scope of the problem context and then search for a design pattern that best fits in that context to solve the problem.  Further, one should have an excellent understanding of the scope and applicability of each design pattern before using it.  Analyze the problem carefully, consider all options and apply the appropriate design pattern to solve the problem.  What I personally feel is that we should only implement a design pattern in our software design provided we have sufficient knowledge of its applicability and scope.  At the same time, we should be able to analyze the problem context and judge the applicability of the correct design pattern (if it is required at all) as a solution to the problem in question.  It is quite unnecessary and not wanted of a software architect to implement a design pattern in a problem domain and increase complexity when it can be solved without using one.