a important skill to success in this world,give your reason and example

I think the knowledge of law is very important in this world for successing.
Because if you don't know about anything of the law,every thing you do can cause a big trouble.
For example,if you want to buy operation system for computer to setup in your office,maybe you can buy one in a very cheap price,but it is illegal software,and you don't know that is wrong,and keep doing the same thing,then perhaps one day you have to pay a very big amount of money for that.
Another example,if you want take a trip to U.S.,and you think the law in the U.S. is the same as Taiwan,that could make a big touble on you.Because the law in the U.S. has some difference in its states,if you don't understand about that,maybe something you do can make you be under arrest in the U.S.,and can not back to Taiwan,that's not good.
Last example is in Singapore,if you want to eat gum,better not in the public place,
once the police see you are eating gum,you will be under arrest,and that is only because you eat
gum,and you will get some very punishment for that,your back will be hurt by stick,trust me,you will never want to taste that.
So these are the reason and examples for my choice,that the knowledge is the important skill to success in the world.