We have a 7 year old dachshund named Pumpkin who was rescued by the Humane Society. The woman was a backyard breeder, and there were over 40 dachshunds rescued. The conditions were deplorable. There were deceased animals on the property. Pumpkin has suffered A LOT of psychological damage that no amount of love and stability can seem to fix, unfortunately. I must bear some resemblance to the woman who mistreated her, because Pumpkin does not fully trust me. We have had her for four years, and she will not let me pick her up. She runs from me if I am walking in her direction. The only time she will come to me is if I am sitting on the floor. It's sad. I do not trust her around smaller children, because she will snap at them out of fear.
On a positive note, she LOVES my oldest daughter, and my daughter is definitely her favorite person in the house. They are best friends.
We have four cats (Beans, Peaches, Cookie, and Jack-Jack), and they all trust me 100%.