During the session we will talk about the causes of painful performance and look into simple and actionable steps how to make a website more performant with a little effort. Most of the examples will be based on a real-life debugging experience. We will dive into the undiscovered areas of Developer Tools and into the basic performance auditing. I will help you understand how browser rendering works and why it can be one of the causes of flawed interaction performance. To leave you with some ideas about where to start your debugging, I will also provide you with examples of UI patterns that are bound to slow down your experience, if implemented incorrectly.