It's your own debt
If Bush had moderated spending the same amount as the tax cut then it would be a true saving. If the tax cut had increased business and government receipts to pay for itself then it would also have been a good thing.
All it did though is just add onto the deficit, and it remains there in all estimates even if the economy recovers. So all you really got is a loan at the same interest rate the federal government pays. And one day you and your descendants will have to pay it, just like any other loan.
So invest it wisely, they'll be wanting it back with interest.