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

7 points here:

1. Seek promotion after sticking to a company more than 2 years.
2. Don’t mix business with your friends.
3. Don’t trust manager, most of them exploit and hunt you if necessary.
4. If you are the best in that company, remember there is another company waiting for you along with better income and better position.
5. Master the art of communicating with clients, boss and other superiors.
6. Don’t be so available for everyone in company, hunters are waiting to exploit you.
7. Know your rate per hour and per month.