Why do dogs hate me so much...

So I can't remember if I posted previously about the pack of cocker spaniels that chase me around the back roads of Stowe occasionally, but there are 4 or 5 of them that will follow me for about half a mile from their house.  They tend not to really cause me any issues so I don't mind them so much. 

However, apparently this isn't an isolated incident.  This week I was running an easy shake-out after a sick fast finish long run so my legs were pretty toasted and because of some pains I've been having in my toe I couldn't run on the trails.  This meant I had to extend my usual 6 mile route to include an extra mile so I decided to run down around the Clocktower place parking lot.  As I am turning around, out of no where a Chihuahua starts chasing me and I figured he would just chill out and follow me for a few and back off, but not this dog.  He decided to continue chasing me and nipping at my ankles, which normally wouldn't be an issue because I could just drop to a lower gear and out run him but my legs were wiped and so I was trying as hard as I could get away but I had nothing.  His owner just stood there watching as if enjoying the situation and eventually called him back.

So I ask....why do dogs want to chase me so badly!