The design behind adding interactivity to an application or website seems trivial; download a free icon collection from sites such as Flaticon, Font Awesome, or iconmonstr, pick an appropriate icon, and add the image to your work. However, should there be more to this process, especially if you are concerned about people understanding how to use what you develop? Learn why the "5-second rule" doesn't apply just to picking food off the floor, how the wrong icon can show cultural insensitivity, why the manner icons are placed in a website or app may be as important as the images themselves, and how to perform icon usability tests. You may be surprised which icons users find to be generally instantly recognizable as to what functions they relate, and which others not so much.