When my Master wanted me to wake him up from a nap at a certain time and I was a few minutes late doing so, he was very disappointed in me. (He had a business meeting) I felt so bad. When he took another nap a few weeks later he set his phone to wake him up because he said he couldn't trust me to do it. I cried. I begged for another chance and he gave it to me after a session with the cane.
I have not been late since. It wasn't the cane but his disappointment in me that did the trick. There is nothing worse than feeling like I let Him down.