By default, much of the text in a Linux terminal is just black letters on a white background. While it has a certain peaceful aesthetic about it, this wall of text is needlessly difficult to “parse” with your eyes. Everyone I know that remained sane while using the terminal for extended periods of time has configured the thing to their personal taste.
As you probably know already, your terminal can display colors. Color can be leveraged to add another dimension of information to the text on your screen and provide helpful marks so you can easily see what’s going on.