I know we have very regular threads on this but I guess this one is just a rant 
My very elderly dog has a serious heart condition, she is also a Springer collie cross so hyper (even at 14 - just falls over more), I have an extendable lead so that she can trot around but I can stop her being too excitable around other dogs.
I live next to a park where the majority of dog walkers seem.to let their dogs off and don't have any control over them.
I'm sick to death of trying to give my dog the small amount of exercise I'm allowed to 3 times a day and keeping her as calm as possible when untrained dogs are trying to leap all over her.
I literally had to get inbetween her and an aggressive young collie who's owner was strolling along at the other side of the park.
Sorry this literally is a rant. I know there is no way to stop it. 