I wanna slap the crap out of my bosses son?

If you've worked anywhere for 10 years you're well over the age the law calls an adult. Kids can generally fight and it gets treated as a kid thing, but if you beat the crap out of this guy without him attacking you first - with witnesses to back you up - you're going to be charged with battery. And even if he attacks you, you can only beat him to the point that he backs off. What I think you need to realize is that this punk, despite all his strutting, feels inferior to you. This is why he uses his father's position as a shield for treating you badly.

If you really, really want to put an end to his harassment, get a small digital recorder and wear it on a cord around your neck and record him harassing you. You need to be on good behavior, basically telling him to go do his own work and leave you alone. When you have a mass of incriminating recordings, arrange a meeting with the father/manager (which you will record) and report his son's behavior and ask him to put a stop to it. If he responds badly or threatens you, take all the recordings to a lawyer for advice before going to the owner. I can't imagine a responsible owner who wouldn't deal harshly with a manager who let his son behave that way, but you never know. Life being not fair, you should have a backup plan in the form of being prepared to seek other employment. Depending on the state or country you live in, this can be considered a very serious legal problem for that manager... and for the owner if he doesn't fix the problem. Check with a lawyer BEFORE revealing any recordings you may make. Good luck.

Start searching for more places to get a job and if you find one, quit and beat the **** out of him.