As others said, it depends on the dog park, people, and time of day, day of week. My daughter said she always avoids the dog park on Sunday. She hears too many people say that their dog has been cooped up all week and Sunday is the day they get out. Way too much crazy energy for her and her dog.
I've tried to do our local dog park now and then, there seem to be different cycles (years) of good and bad. Currently there are some women there who think they own the park, and are rude. In previous years I've found very caring people, but I'm sure their dogs have died by now.
There is a very small dog park across from my mom's in Davis, CA. When I go to visit I find such a different, nicer attitude from the one near my house. I don't want to sound snobbish, but it is a university town and has many college grads and graduate students there, the young and better educated, open minded people with their dogs are so nice and accepting of me and my big GSD. My dog picks up on this and is super nice to all the dogs and people there.
A good thing to do if you can is walk around the outside of the park first and get a feel for the dogs and the energy at the moment. If it seems good, then enter.