I've decided to stop going to dog parks. If I do, then it needs to be near-empty. I used to take my puppy there all the time once she got her shots. I liked going because I learned a lot about my dog and other people, but now it's getting too risky. Although she's only 40 lbs. she has no concept of her size and loves to play with much bigger dogs (100 lbs.+). It's also mainly because I don't trust other people with their dogs, especially when they come in cliques that meet every other evening or so.
My pup isn't DA but she will zone in and pick on insecure/nervous dogs, especially if they are vocal and small(er). She'd taunt them and want to play. She's gotten a lot better about leaving those types of dogs alone, especially if I'm close enough to just stand/walk in her way. Either way, too much of a risk. People have and will misconstrue her play behavior as aggression.
I also hate it when other owners start talking to you about how to raise your dog. Most park people are average pet owners and do not need to pay attention to their dogs as much as those who work their animals.