The Difference Between Gross and Net

There was an interesting point brought up on Til Debt To Us Part. She said that most people think of how much they make in terms of before taxes and their expenses in terms of before sales taxes as well. So they make more then they think they do and they always think that they are spending less than what they really are. She broke down how much something would actually cost you in net pay, as in what you take home after taxes. So, you can still buy nice houses or a diamond tennis bracelet as long as you really know what you are taking home. This was really eye opening. So how do you think about your money, gross or net?