Puppy Playtime is so important to a pup it's as important as food! Without proper socialization dogs simply don't learn social structure and bite inhibition. It's important however that one has a balanced and well socialized, well matched, appropriate friend to play with. This is important so that good lessons are taught to the pup, not inappropriate rude behaviors.
Training is also very important but I would never put training over the importance of socialization. It's fairly easy to teach sit, down, stay, at almost any age. These behaviors are used to replace inappropriate behaviors in teaching house manners. So training is definitely necessary for a dog to live a happy life and is a must.
However, for a pup to learn the skill of communication with other dogs and through that gain confidence is invaluable. A confident dog is less likely to react to other dogs in various scenarios. A dog that has acquired bite inhibition through play is less likely to do damage later in life IF he ever does bite in a very stressful moment. Many things influence whether or not a dog is reactive to other dogs throughout his life but socializing can be a very helpful tool in setting a dog up for success.
These two dogs were introduced the canine way, in other words not face to face before they knew each other. For example let dogs hang around (not staring at each other) or walk side by side before greeting. Bree is shown here playing with her buddy after hard work at training class. Her lessens learned from this nicely balanced pooch buddy will we invaluable throughout her life.
This is the best way to have a play session end....calm and relaxed. When you get to this point call it a day, tell your pup with calm praise how great she did. Pups like small children tend to get cranky if play goes on and on especially after the point shown here. So pack up, say thanks and go home for a long nap! Enjoy!