Hollywood misleads us about many things - it convinced us that frogs say "ribbit" (there's only one kind of frog that says that and it lives in the Hollywood Hills), that cars explode after a crash (this is very rare), and that if a person says they're not interested, stalking them until they capitulate is super romantic and not at all a great way to get arrested or at least blacklisted (this is actually wrong).
One thing Hollywood did get right, however, is dogs. The movies are right about dogs on multiple levels. They correctly portray dogs as the most honorable, loyal, friendly, and intelligent friends humans can have. They show that dogs can be incredibly funny and may have their own sort-of sense of humor. They show that if a person doesn't like dogs, they suffer from some kind of damage or trust issue that may be resolved - and if it is, then they will start liking dogs.
If they actively go out of their way to abuse dogs, they are simply beyond help and definitely not likely to turn around at the last minute and renounce their supervillainous ways (you can try this in real life; it works). They also inform us about a character by showing what sort of dog they have and how they interact with it.
That's why it's possible to know a great deal about a person just from knowing what kind of dog they have... and vice versa! So tell us about you, and we'll guess your dog!