Disengagement from different stimuli is one of the biggest things that I train for dogs. Disengagement is training your dog to be calm with any stimuli (including cats, children, people, other dogs, livestock, horses, etc).
As a Puppy:
Add this into your socialisation training for your puppy. Yes it's important for your puppy to meet and interact with other dogs but if were allow this with every dog then it can develop into frustration reactivity (where your dog will lung or vocalise because they really want to meet every dog) or with larger breeds they could pull you over to meet every dog. I like to train a release cue to meet other dogs and socialise early on and also train puppies to walk past other dogs without saying hello so they are calm and in control around other dogs,.
For Fearful or Reactive dogs
hThis is so important for fearful dogs. The ability to look away from their fear triggers means they are more comfortable and relaxed. This starts at a threshold away from the trigger and as your dog gets more comfortable, you can build this threshold closer. Anytime your dog looks away from the trigger, they get a reward. With repetition, this also changes your dogs emotional response to the trigger. Where the trigger used to be scary, it is now an indicator for food and therefor is no longer scary.