I think Ricky is very sensitive. His Vet even said that he is like a lot of Chihuahua he sees. He is very loving and loves to be held (we love holding him so that isn't a problem).
The only time he gets excited like he might attack someone is when he hears noises outside our house or motorhome or if some one goes to hug me and pats me on the back. He thinks they are hitting me and starts growling. I am trying to make him understand that pats on the back are not hits.
Ricky has never been hit, yelled at etc. He has never been left at a kennel or with anyone other than our family that lives in this house together. Everyone loves him so I think he may just be that way. He is the smallest from his litter and his brother from the same litter is 13 lbs so there were big size differences. Maybe that is where it started.