Ok, I had Tiger tonight from 530 until 945. We played inside, we went for a walk, we went back inside, then we went to the dog park for about 2 hours. Tiger played and had so much fun. Play-break-play-break...you get the idea. We headed home, I knocked on the door and his owner came out. Instead of going to her, he went to my apartment door. He ignored her for like 5 minutes. Xerxes was more interested in going inside her apartment than Tiger was. I felt like shouting to her "See what positive reinforcement can do?!?!?!"
Instead I talked with her about the benefits of +R and exercise. At least I know he'll sleep well tonight with no acting out.