`close()` shuts down only the current window in focus. If multiple windows are open, the others remain active. `quit()` kills the entire WebDriver session, closes all open windows and tabs, and stops the driver executable process completely.
close() is like closing one tab in your browser. quit() is like closing the entire browser application.
You notice that after running 10 tests, your computer has 10 'chromedriver.exe' processes running in the background. Which command were you likely using?