Well one went because he chose his mobile phone over work, there is not a lot I can do about that. One left because he lost his driving license and could no longer get to work. Other than the mobile phone I had no issues with them
Now the third one. I did not work much with him. But how do you motivate someone who deliberately does half a job, lies, refuses to do what you ask him and answers back. Well I got sick it so I grabbed him by the throat slammed him against a wall put my fist to his face and shouted "answer back to me once more and I'll smash your face in". Well that stopped the answering back but he still had no interest in the job so he was fired. You cannot force them to be interested.