Character tags

When you are developing a character, unless a minor one (and even then you might) you should give your character a tag, some quirk or mannerism that he/she does that sets her apart from your other characters. It’s even better if you can use this tag as part of your storyline. For example, a woman who rambles or chatters too much when she is nervous could give something away that she normally wouldn’t have if she hadn’t been nervous. Or someone carrying around an item that he feels brings him luck, then have him lose the item as part of the plot. The tags can be funny or serious. The tag will help your readers more easily identify the character and keep that one straight from the other ones you have in your story. What are some of the tags you have enjoyed the most in characters you have developed or read about?