Question: Why do dogs pull on leashes?
Answer: Because people follow.
To the OP - first I wouldn't let the dog pull me anywhere - dog parks, whatever. If he pulls, I stop walking. The minute the leash gets slack, we walk again. Bring lots of patience. Pulling is a dominant behavior and isn't helping your home situation.
To the other posters - if the dog is barking & lunging, distracting with treats & toys COULD be seen as a reward by the dog. I had this with Zack. We did Control Unleashed where we started with the other dog far away. Going for a walk, we might need to cross the street to get distance. He looks at the dog "Good boy!" and gets a treat. Before you know it, your dog is looking at the other dog & then looking at you for the treat. Hey! Dogs are good! Thanks for the cookie, buddy!
Now, we can pass most dogs without getting paid. But, if there is a particularly aggressive dog who is lunging at Zack, Zack turns to me like "Pay Up!"
The whole idea is that the dog DOES look at the distraction but then turns his attention to you. Jerking the dog & getting excited just exacerbates the problem. Pull on the dog, they pull back. The analogy I learned was - if you're really afraid of snakes & somebody put a rattle snake right behind you - you can hear it rattling, but every time you turn to look, you get jerked away - wouldn't you figure out that "snakes = very bad." OTOH, if you saw the snake from a distance & somebody handed you something delicious - maybe snakes might not be so bad after all.
Lastly, Zack has little dog-sniff tolerance. He's good for about five seconds but then he wants to play, which means "I jump on you & you like it." So, he gets about three second sniffs then, "Good boy!" a cookie & we continue on our way. I want every encounter to be a GOOD encounter. That's where a halti is nice - I can control his head with a "good boy" e.g., take it out of the other dog's rear area & we're on our way.
He ain't perfect and I'm not a perfect trainer, but so far, this has worked the best for both of us.
To train a dog, you must be more interesting than dirt.