There are no bad dogs. Only bad owners.
I have had several breeds that have thrived because we treat them like a part of our family, but train them well as puppies as to what is acceptable of them. Once they know their boundries it all goes well.
My next dog will be a Chihuahua. Going to name him Cujo.
I had a teacup chihuahua that would not train for me. I tried for the better part of 8 YEARS, and he just would not stop some of his bad behaviours. I gave him to my GF, and he responded to her nearly instantly, and is a very well-behaved little gentleman. He needed a small pack to blend in with, and when I lost my other dog the chi went stupid-er.