I have been known to be a bit stubborn.
I won't shop at stores if I learn that they don't have a bathroom for customers. (Not only is this one practical, but I firmly believe that if you're willing to take someone's money, you should be willing to let them use your toilet as well.) I think gift certificates should not have an expiration date, and have had chats with many a manager over this. (They still have all your money, right?) And I do not share desserts unless the terms of the dessert sharing were agreed upon before said dessert was ordered.
While some people might see these habits as idiosyncrasies, or just kind of odd/difficult, I think it's my commitment to these rules that pushes me into the stubborn territory. No bathroom for customers? You really will never see me in your store again -- unless of course I hear a change in policy has occurred.
But, perhaps the best example of my stubborn streak is what happened in my computer class from the fifth through the seventh grade.
Once or twice a week, we had to go to something called computer class. (I've honestly tried to block this particular part of my elementary education out, so the details on time might be a bit off.) There wasn't much to the curriculum -- we did typing tutorials for 45 minutes. Each and every time. For three years.
We learned absolutely nothing else about computers, and the only incentive to complete the typing tutorials was that if you finished early, you could play computer games.
Now, it just so happened that computer class was taught by one of my least favorite teachers. I thought he was cocky, condescending and seemed far more interested in what the boys had to say than what the girls had to say. For this last reason alone, he was really at the bottom of my list.