Smiley images and the text used to produce them*:

In some instances, multiple text options are available to display the same smiley.

Why Doesn’t it Work for Me?

If smileys work for others at your site but not for you:

Type a space before and after your smiley text. That prevents the smiley being accidentally included in the text around it.

Make sure not to use quotes or other punctuation marks before and after the smiley text.

via Using Smilies « WordPress Codex.

This is just for personal reference.