Every software engineer and architect strives to design modular software systems and avoid complexity. Yet, frequently, the outcome is the opposite: what promised to be an elegant, well-thought architecture results in another big ball of mud. Why does this sad story keep repeating? In this talk, we will explore the nature of modularity and complexity, including their surprising similarities, and delve into the socio-technical design decisions that influence these outcomes. Additionally, we will demonstrate how the same forces that push software design towards modularity and complexity are also relevant in organizational design. By understanding both the technical and organizational dimensions that impact software development, you will learn to harness these forces to design systems that not only withstand changes but also thrive over time.