11. Cocker Spaniel

Originally bred as flushing dogs that worked closely with hunters in the field, Cocker Spaniels maintain a strong desire to stay right by your side. While it is normal for a Cocker to follow you from room to room, they often cross the line from normal breed clinginess into true separation distress.

If your Cocker Spaniel cannot settle and self-soothe when you go to the bathroom, they need help building independence. Teaching a strong “place” command—rewarding them for staying on a specific dog bed while you move around the house—helps them learn that they are safe even when you are not physically touching them.

12. Chihuahua

Chihuahuas are tiny dogs living in a giant, intimidating world. Their small stature means that heavy footsteps, loud noises, and looming strangers represent genuine physical threats. This vulnerability often manifests as defensive anxiety, which looks like growling, snapping, or excessive barking.

While it is tempting to scoop a frightened Chihuahua into your arms, constantly carrying them prevents them from learning how to navigate the world safely. You can build a Chihuahua’s confidence by allowing them to approach new things on their own four paws, at their own pace, rewarding their bravery with tiny treats.