<human>:  What is the difference between Windows and Mac operating systems?
<bot>: The biggest difference between Windows and Mac operating systems is that Windows is developed and marketed by Microsoft, while Mac is developed and sold by Apple. Additionally, Windows uses a graphical user interface (GUI) that is designed for users to interact with their computer by using a mouse and keyboard, while Mac uses a different type of GUI called Aqua. Additionally, Windows is a closed-source operating system, while Mac is open-source and allows users to customize their computer's settings more extensively. Finally, Macs are generally more expensive than Windows computers.