When a dog starts chasing you, do you really have time to determine if the dog is just chasing for fun and will stop after a short while, chasing to protect it's territory (yard) and will stop once you pass by, or chasing to attack you and won't stop until it's either out-run or bites?
Of course, the first thing I will do is yell "GO HOME!" or even "SIT!". But, while I'm doing that, I'm reaching into my jersey pocket to grab my HALT spray cannister. If the dog comes within range, I don't take chances. The dog gets a face full of spray. (Personal experience, water doesn't always work.) Stopping may work sometimes, but if it's a particularly vicious dog, you could be standing there for a long time before the dog either gets bored or finally gets to sink it's teeth into you.