What prevents people from making good decisions—even when all the facts support them? This chapter explores the often unconscious thinking patterns that shape our behavior: cognitive biases and mental shortcuts, known as heuristics. Drawing on my experience from thousands of conversations with entrepreneurs, I illustrate which thinking errors occur particularly frequently—and why they can significantly hinder sound decision-making in leadership, sales, and strategy. Using concrete examples from my consulting practice, I demonstrate how typical stumbling blocks such as loss aversion, confirmation bias, the false consensus effect, or single-option aversion influence decisions within organizations and throughout the sales process. Furthermore, I show how to recognize these biases, skillfully work around them, or deliberately counteract them—in order to ensure that communication does not fall flat, but instead effectively inspires meaningful change.