Is it possible to over socialize a dog?

Socialization is habituation to the environment through exposure. Lots of good exposure is not harmful. You definitely need to be attuned to your own dog and cultivate experiences where your pup feels safe. Your puppy needs a lot of rest so you don't want to exhaust and burn them out. But continuous social exposure to sensory stimuli will, if anything, lead to habituation and satiation. In other words people/places become old news and less interesting to your dog so they focus on you more. If your dog lacks impulse control and wants to run and greet every dog and human they see, and becomes frustrated and acts out if they can't, this is a training issue, not a socialization issue. Overwhelming stressful exposure is harmful.

He wants to meet like EVERY dog on the street. To the point he would pull like crazy toward them barking and howling in desperation to meet. This makes it seem like he’s a wild dog but he’s very good with others. His threshold to go nuts is like 10 meters. My question is did we over socialize him meeting way to many dogs and giving him the expectation that he gets to see and meet them all the time. We tried our best to work with our trainer and dog walker to introduce him to calm dogs and get him socialized to people. It worked great to the point he’s way more comfortable outside and way more with strangers.

Daycare can be a great tool, but people make the mistake of over socializing their dog to the point where they get sick of it and become reactive or even dog on dog aggressive. When they do this they flood the dog with that stimuli. The more you keep bringing them, the chances of them getting confident and picking up these reactive dog behaviors increases. Some dogs it takes weeks of that for them to become reactive, some less, some not at all. More socialization is not the key. Proper communication and structure is the key to fixing reactive behaviors and preventing them. If you have a happy go lucky dog, then occasional interactions is all they need, more than once a week daycare I think can turn these types of dogs to be reactive. The bottom line is you do not need to overdo socializing your pet, you should take your dog out and get them accumulated to dogs, people, new places, noises, etc. Again daycare is one of those great socialization tools, just don’t overdo it and have your plan backfire.