While our brains are conveniently set to auto white balance and our eyes view a properly adjusted color temperature, our cameras, try as they may, are not quite as advanced and sometimes rely on us to provide assistance to them. For our image color and tone to be as accurate as possible, we have to command control of this setting ourselves.
Taking that control is part of the process: read the light in the scene, adjust your camera’s color temperature accordingly, or as many do, keep the default AWB setting where it is, and if necessary fine-tune in post. Often, your camera’s AWB will suffice, but where controlling white balance really gets interesting is when we are dealing with mixed lighting sources or when we start to introduce lighting into the environment. As photographers, the most common way we do that is with flash, thus adding additional layers of light at different temperatures, further confusing the camera. If the camera is left to its devices, it will often struggle and leave you with a Frankenstein mix of colors.
Jeff Remas provides us a nice breakdown with basic and concise explanation of camera white balance. He covers causes of overly blue, yellow, and green tint in our images and displays multiple examples of Kelvin, showcasing, for example, what to expect from our images if lighting our subject with flash at 5500K against a fading sunset background at 3200K. It's all incredibly useful knowledge to brush up on and apply into the purposeful crafting of your images.