What are the biggest lessons you have learned in the corporate world?

5 points here: -Seek promotion after sticking to a company more than 2 years. -Don’t mix business with your friends. -Don’t trust manager, most of them exploit and hunt you if necessary. -If you are the best in that company, remember there is another company waiting for you along with better income and better position. -Master the art of communicating with clients, boss and other superiors.