Woof.

1. You need to have TONS of dog t-shirts.

2. You have a pet dog.

3. You know how to bark properly.

4. You know basically all the dog breeds that there are.

5. You have a favorite dog breed.

6. You very good at drawing dogs, and you concentrate on drawing dogs, and that's how you became really good at doing that.

7. Your OC is a dog, or has a pet dog.

8. All your fanfics have a dog as a main character/main character's pet. 

9. You are absolutely against cats. ABSOLUTELY.

10. You talk about dogs all the time!!!!

Note that this may not apply to you, but it applies to some others that I know. If you want me to do a particular subject/fandom, please PM me with 10 ways! :)