To design something intuitively is to design it so that users don't have to dedicate cognitive effort to figure out how something works. The idea at the core of intuitive design is that it just works.

When we write code, we are partaking in its design, its grand architecture, its functionality, and its line-by-line syntax. All of these are vital parts of that design. Using intuitive patterns of design is vital to crafting usable code. All users are attuned to a set of patterns that are employed on their level of abstraction. Here are some examples:

• In a GUI: Using an X button to indicate exiting a program or process
• In code: A function or method starting with is indicates a Boolean return value
• In a GUI: Using green for affirmative actions and red for negative actions
• In code: Upper-casing constants, for example, VARIABLE_NAME
• In a GUI: Using a floppy disk icon to indicate the concept of saving

These are the assumptions and expectations that many users carry around with them as they navigate software. Tapping into these assumptions means that your code and the interactions it facilitates can be monumentally easier to use.