Since 10.8 Apple has had emoji icons built into the OS. Until recently, I used these for Twitter and IM, but not much else. Turns out, they’re actually really handy other places too.
In Evernote I use them to easily identify some of my notes. In calendar, I can add palm trees to my vacation. Even in the finder you can add icons to your folder names.
You can add them to bookmarks in Safari and Chrome too, however they’re kind of small.
iTunes playlists can be emoji icons as well which is kind of fun. There are plenty of smilies for whatever mood your playlist happens to be. Add hearts for romantic playlists, or a bikini to your poolside mix.
To make it even better, the icons work just fine in iOS.
Now I’m not saying you should go emoji icon crazy, but they can actually be a nice addition to typically boring text.