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.