Operation Kindness in Carollton is the largest no-kill shelter in the DFW area. My parents got our family dog there in 1988, and I got the first of my two cats there in 2000. I also volunteered there for about a year prior to moving. You can tell the volunteers and staff alike really care for the animals. If you have concerns about adopting a specific animal such as behavioral problems or will the animal get along with other pets or children, the adoption counselor can answer your questions. You do have to go through an adoption interview because the shelter is very serious about making sure the animals adopted out go to good homes and don't have to come back to the shelter. It is, however, a pleasant experience. I also highly recommend volunteering there.