My experience was like CLB's. I tried to get Timber (rehomed TAG) to step up immediately after I got him. The first couple of times, he did. After a few days, the honeymoon was over and he started biting me when I tried to get him to step op. Based on advice I read on this forum. I just started leaving his door open and not trying to get him to step up. When he started trusting me and I wanted to try again, I followed more advice I read here and remembered to never ask him to step up unless I was going to take him somewhere he wanted to go so it would be a positive experience for him. Now, we are doing well. He's bitten me a couple of times, but he had his reasons!