Ruby symbols are not just pretty strings:

If you’ve ever written a program you’ve probably heard that “premature optimization is the root of all evil.” Well, that doesn’t mean you should ignore performance considerations entirely. As Ezra Zygmuntowicz says, “Postmature optimization is the root of all hosting bills.” If cutting corners means you can get your code written faster, then by all means throw performance to the wind and write code at warp speed. But why incur a performance penalty when you get nothing for it?