While we may not assume for certain what our dogs are thinking at any given moment, we can make informed guesses as to what may trigger the behaviors that drive you crazy. That, and the fact that no one knows your dog like you do, will help you get to the bottom of these issues! Like I discussed earlier in this chapter, understanding the likely motivations behind your dog’s behavior is the best place to start. So, here are the six biggest culprits.

Insufficient Exercise

Want to know the biggest life hack in dog training? It’s that exercise resolves most problems. See, it turns out that most of the reactive, misbehaving, out-of-control dogs are the ones who don’t have enough of an outlet for their energy. Remember, 90 percent of unwanted behaviors are due to a lack of exercise and the fact that a dog is simply bored! That’s 90 percent!

Most annoying habits, anxieties, or hyperactivity can be mitigated greatly with the right kind of exercise. As I explained on this page, chapter 1, if your dog has an abundance of energy, exercising him early in the day with structured activities like fetch that involve working with a person should satisfy him for a good portion of the day. Regular exercise can even help lower-energy dogs, too, especially regarding issues relating to anxiety and fear.

Also, in the earlier stages of training, it’s not even reasonable to expect many unexercised dogs to comply with your requests—especially those mid- to high-energy dogs. Only when your dog has released that energy can he calm down enough to focus on you for the training session.


Clearly, genetics plays a part in governing how a dog behaves. In fact, a dog’s behavior is based on the culmination of his experiences and his genetics. Think about the countless possible combinations you can have of those two things!

Change in the Environment

The single fastest way to cause a dog to act uncharacteristically is to change his environment. This is one of those things that you don’t account for if you’re new to dogs. Environment matters!

As people, we notice a change in the environment ourselves. Think about how you feel when going from a quiet car into a crowded sports stadium or concert, for example. Or how you feel when first entering a party where you don’t know a lot of people. The difference is that we’ve had many years to adjust to and manage such situations. However, don’t forget that when you were a toddler, you might have had a meltdown when first experiencing a new place like preschool or even a movie theater. In this respect, dogs are like toddlers.

Medical Issues

Sometimes a dog’s behavioral issue seems to appear suddenly and out of nowhere when there’s been no major change to your dog’s life or environment. For example, if your dog starts consistently peeing inside the house and you haven’t recently moved, then he might have a UTI or other medical issue. Sometimes a dog may growl, nip, or snap at a person or animal uncharacteristically. He might seem extra-anxious. He could suddenly become totally lethargic. These could be signs that a dog is in some type of pain: he might have a stomachache or dental issue or something more serious such as thyroid disease or other illness.

We can all relate to this. Sometimes we don’t feel well and are less likely to be in a pleasant mood. We might become grumpy, exhausted, and antisocial. Dogs are no different in this respect. Nobody knows your dog like you do, and you’ll likely be the first to realize that something’s off with him. Of course, the best way to determine if a medical issue is causing your dog to behave in a way that’s not typical is to visit your vet to get to the bottom of it.

Lack of Socialization

A lack of socialization at a young age seems to be a major cause of behavioral issues in dogs. In fact, the American Veterinary Medical Association says that the socialization period—which occurs primarily between six and fourteen weeks—is the time of life for a puppy when “providing diverse, positive experiences can prevent the development of fearful responses and subsequent behavioral problems.”10

Why is this the case? Like humans, dogs are impressionable. Certain events and experiences can contribute to how a dog is likely to react to those things in the future. For example, if a puppy experiences a kid pulling his tail, the puppy may continue to assume smaller humans with higher-pitched voices are likely to cause harm or annoyance.

Also, if a puppy is simply not exposed to something frequently enough, then he may become overexcited, fearful, or even aggressive when he later encounters that thing. As another example, it seems that a lot of dogs are fearful of men. It could be that a dog had a negative experience with a man when he was a puppy. Or he might not have been exposed to men enough when he was younger.

A Lapse in Training

Never blame your dog! It’s easy to hold dogs to a high standard because they usually demonstrate how smart they really are at a very young age. So we assume that if they’re not conforming to our expectations, then it must be their fault. However, if your dog chews something up, has an accident in the house, or consistently jumps all over houseguests, then you must understand that that’s a reflection of how well you have taught your dog the fundamentals.