A "hard stare" is one that is direct eye contact, tight muscles around the eyes, and held for longer than 2-3 seconds. The dog feels threatened and may choose to escalate to more obvious stress signals like growling, snarling, or snapping. 

"Whale eye" is when a dog's face is pointed in one direction and the eyes are pointed to the side, towards whatever it is that is threatening them. It looks like avoidance, and it is.  The dog feels threatened and may choose to escalate to more obvious stress signals like growling, snarling, or snapping. 

"Slow blinks" or "squinting" is a sign that a dog is nervous or upset, trying to avoid a confrontation. This is commonly mislabeled as "guilt", however dogs do not experience guilt as their brain does not contain the area that controls a moral compass. They do not know right from wrong - they know what works and what doesn't. 

Backward and tight to the head - they may be fearful or nervous, wanting to get away. 

Low - they may be uncertain and wanting to avoid the conflict. 

One alert and one pointed away - they may be slightly distracted by a sound but not motivated enough or comfortable enough to turn their head away to alert to it. 

Relaxed tail - when a dog's tail is held in its natural carriage, whatever that might be.

Flag tail - when a dog's tail is held high like a flagpole, and stiff, they may be alerting to, or anticipating something concerning. 

High tail - when a dog's tail is held high but not tight like a flagpole, they are likely alerting to, or anticipating something exciting.

Low tail - when a dog's tail is held low but not tucked, they may be feeling anxious or uncertain. Sometimes the tip is wagging slowly due to that uncertainty.

Tucked tail - when a dog's tail is clamped down over their "exit point" (ahem.) and tucked between their legs, they are feeling fearful, anxious, scared. 

The wagging and movement tells a lot too. The more stiff and still the tail is, the more likely it is that they are tense and concerned. The more loose and wiggly the tail is, the more likely it is that they are happy and excited. 

Remember to pair it with the rest of the body! A wagging tail is NOT a happy dog; a wagging tail is a dog who is aroused. You need the rest of the body to form a full story. 

A tight wag is not happy. A wide wag is happy. A helicopter tail is the happiest dog, especially if it's whipping in a counter-clockwise direction! 

Some great info about a dog's emotional state can be gleaned from their mouth, so let's explore that! 

Dogs can "smile" by loosening their jaw and allowing their mouth to either remain softly closed or open with a relaxed tongue. You should also see the rest of the components relaxed as well - the eyes, ears, tail, etc. 

When the mouth is open but the commissures are pulled back in a > shape, the dog is likely stressed, very over-exerted or recovering from stress.

* If the tongue pulled back behind the teeth while the commissures are pulled back in a > shape, the dog is stressed and might escalate into a bark, air snap, or bite. 

When the mouth is open but the commissures are pulled back in a C-shape, the dog is likely hot, excited, or happy. 

The tight mouth - this signifies fear, anxiety, stress, or frustration. Not an approachable dog. 

The tongue flick - oftentimes dogs like this are feeling a little apprehensive and might need some space.

The agonistic pucker - this is what dogs do to warn off a threat. This is a mouth we don't want to get close to! Their lips a puckered up tight and pulled forward with their whiskers, their nose wrinkles, and their teeth are showing. "This is what I will do if you don't stop that now" is what they're saying. Time to back off! 

The "grin" - there are two reasons for this grin - one is that the dog is friendly but a little uncomfortable. The other is that they are trying to appease us - "please don't fight with me - let's work this out peacefully!"