The core of the problem is that people often confuse “parameterization” with “abstraction”: Parameterization is simply adding adjustable knobs. For example, a

The core of the problem is that people often confuse “parameterization” with “abstraction”: Parameterization is simply adding adjustable knobs. For example, a function can take as argument a gigantic list of flags, where each particular combination of flags makes the function do something slightly different. Abstraction is actually separating concerns. It's dividing a program in logically independent parts, whose correctness can be established individually, without worrying about the others. Abstraction means that software components only interact with each other through explicitly designated interfaces, often enforced by the programming language itself. Parameterizing is easy. Abstracting is difficult. Unfortunately, parameterization without abstraction is a source of headaches in the long run.