Dog

Direct and staring look: Challenging, or the answer to a challenge by a dominating dog.

Straight look: The dog feels safe.

Eyes slightly closed: Response to a dog submitting to a challenge. Accepting submission.

Eyes half closed: The dog is enjoying the moment. This is the look they have when they are petted.

Avoiding look: Deference.

Sideway glance: It is shy or it wants to play. This is a proper way of showing interest for something without being demanding.

Casual visual contact: Happiness.

Dilated pupils: Scared.