Hacking is a high-risk, high-reward, with a high-cost to human capital. In this session, we will talk about the effects of human factors in cyber operations and why you should care about them. Specifically, we will focus on results of research at the National Security Agency that studied the effects of cognitive stress on tactical cyber operators. A key motivation for this work was the intuition that cognitive stress may negatively affect operational security, work performance, and employee satisfaction. Operator fatigue, frustration, and cognitive workload increases significantly over the course of a tactical cyber operation. Fatigue and frustration are correlated, and as one increases so does the other. The longer the operation, the greater the mental demand, physical demand, time pressure, frustration, and overall effort needed to complete the operation. Operations longer than 5 hours have 10% greater increases in fatigue and frustration compared to shorter operations. We found no link of performance to operation length; that is, from the operator's perspective longer operations did not result in higher success. Knowing how these factors affect cyber operations has helped us make more informed decisions about mission policy and workforce health. We hope that by sharing this with the greater Black Hat community, they will also be able to learn from our study and improve their own cybersecurity operations.