I'm wary. As others have said, if I see something that doesn't seem right, I get out of there. So far, it's only applied to dogs, and so far only urban dogs. I think urban dogs are easier to deal with because they are usually alone, and usually defending a specific yard, so once you're past their turf, they leave you alone. I use a combination of avoidance, yelling (Yo Spiff taught me that) and water bottle squirting to ward them off; it's worked so far. When it comes to avoidance, I seem to have developed pretty good dog radar. I almost always see them before they see me.

When it comes to people, my defense is in trying to be unobtrusive. I don't ride fancy bikes through crappy neighborhoods. I generally stick to routes I am familiar with, and stay away from new routes after dark whenever I can. When I do pass people by, I greet them- say hi, ring my bell, smile. Even a thug usually smiles at a dork rockin' a bell on his bike. It puts them off their game.