If you are coming in late for work, the boss will lose precious time and the things that were need to be done wouldn't be done. He can easily get you fired if you are late for too many times at work and simply get someone else to do the job better. but yet it depends on how much wanted his job is, if it is an unwanted one then he won't fire you that easily, but we can never know what the boss will do since there are people who are unexpected.