Dogs enjoy fetch primarily due to their natural instincts for retrieving objects, which stems from their ancestral roles as hunting or retrieving breeds. This activity provides mental stimulation, physical exercise, and opportunities for bonding with their owners. The excitement of chasing and retrieving a toy, coupled with rewards and praise, makes fetch a highly enjoyable and rewarding game for most dogs.

Here's a step-by-step guide to help you teach your dog to fetch:

1. Choose the Right Toy: Start with a toy that your dog is interested in. It could be a ball, a favorite plush toy, or a frisbee. Make sure it's something safe for your dog to carry and retrieve.

2. Introduce the Toy: Show the toy to your dog and let them sniff it. Encourage interest by playing with the toy yourself and showing enthusiasm.

3. Encourage Retrieval: Toss the toy a short distance away from you. If your dog shows interest or starts to move towards the toy, praise them and encourage them to go get it.

4. Use Commands: Introduce simple commands like "fetch" or "go get it" while you're tossing the toy. Consistently use the same command each time you play.

5. Reward Success: When your dog retrieves the toy and brings it back to you, reward them with praise, treats, or a combination of both. Make the reward immediate and enthusiastic to reinforce the behavior. If your dog doesn't want to drop the toy, sometimes it helps to have another toy that's equal value. Show your dog the second toy and he/she should drop the toy they retrieved.
   

6. Repeat and Extend: Practice the fetch game in short sessions, gradually increasing the distance you throw the toy. Start with short distances and gradually increase as your dog becomes more confident and skilled.

7. Patience and Persistence: Some dogs may take longer to learn than others, so be patient and persistent. Keep the training sessions fun and engaging to maintain your dog's interest.

8. Avoid Chasing: If your dog doesn't bring the toy back immediately, avoid chasing them. Instead, use a cheerful tone to encourage them to return with the toy. Chasing can turn the game into a game of keep-away rather than fetch.

9. Consistency: Consistency is key in dog training. Practice the fetch game regularly and be consistent with your commands and rewards.

10. End on a Positive Note: Always end training sessions on a positive note, even if progress is slow. This will keep your dog excited and engaged for future training sessions.

Remember that every dog is different, so be patient and adapt your training methods to suit your dog's personality and learning style. With time, practice, and positive reinforcement, most dogs can learn to fetch and enjoy this interactive game with their owners. Utilize this training to introduce additional commands such as "Take It" (for the dog to take the toy) and "Drop It" (for the dog to release the toy from its mouth).