I don't either. Some Pokémon seem to like fighting, but unless you're feeding yourself or defending yourself or someone else you shouldn't hurt anyone. I try to avoid fighting other Pokémon while I'm traveling and I tell the Pokémon with me to make sure that the Pokémon they meet want to fight before they attack. They really wanted to challenge some of the gyms so I let them, but I'm not going to try to win all of the badges like some people do.