I've cared for many medium-sized bearded dragons that were friendly an docile. If they are handled throughout their life they will enjoy the company of humans, but if the one you had was wild caught at an advanced age or bred in captivity but never properly handled you will have a hard time making a good pet of him.
One good place to get a friendly medium to large sized bearded dragon is from a young person going off to school. Most schools don't allow large reptiles in the dorms, and parents who aren't interested in the dragon find feeding and cleaning up after reptiles unpleasant, so the owner is forced to find him a new home. Start your search online or in classified ads shortly before school starts, and make sure you can handle the dragon comfortably before you take him home.
Also, you need to take some time educating your self about the care of your pet. There is a lot you need to know to properly care for a bearded dragon. The folks at the pet store can tell you the basics, but you need to do further research. There is a lot of information online and there are some good books that will help you.