Abuse of power in the workplace....wheres the line? How do you keep your cool.

So i work for mavis discount tire warehouse and i pick tires. Not the best job in the world to some but it pays the bills. Now there is an employee that i work with who isnt the boss he has a key to get into the building so he is a higher up but he is not my boss. I suppose the best way to put it is the guy thinks he should be the boss and everyone else isnt worth the dirt on his shoes. Now there already as you can see is an abuse of power a tad bit. Two weeks ago my phone was stolen from my machine at work so if anyone touches anything on my machine i would freak out. Now if your a little late he is sure to say something as well. Yesterday he showed up twenty minutes late and told me the machine i had was his, these machines are not designated first come first serve. I got upset because he told me to get off the machine it was his and i replied with maybe if you were here on time you would have the machine. Thereafter i went to smoke and returned to my stuff moved off my machine, and i went off on him and told him not to touch my things and he tried to write me up for insubordination. i wasnt written up because he knows he was in the wrong.

I must confess i didn't handle the situation 100% the right way but the abuse of power sometimes is overbearing. Employers always have that one employee that likes to abuse their so called power. Through the years ive had many employers like this and ive left jobs because of it. The term employees don't give up on the job they give up on the employers. Now that i have a son i can no longer afford to just do and say what i want. so i just try to take a breath and let it go but sometimes my anger gets the best of me. Im sure that most of you can relate to my situation. How are some ways you guys not freak out at work when someone abuses their so called power at work. Thanks!!!!