There needs to be more enforcement of leash laws in Golden Gate Park on Sundays. It is great that the close the streets so that people can ride, skate, walk or whatever through that area, but there are too many off-leash dogs.
Dogs are unpredictable, have little traffic sense and present a hazard to bikes. Plus many people (particularly children) are uncomfortable around dogs. Too many dog owners think there dog is just "friendly" but then when it knocks someone over or bites someone they say "oh, it has never done that before".
Leash laws exist for a reason and it is very selfish for people with dogs to endanger others by not obeying them.