TimeQuest Timing Analyzer[Setup slack analysis]

I have recently been involved with xilinx vivado that is replacing ISE and specifically it is xilinx attempt to catch up with timequest. They follow the same standards of synopsis sdc. Their documentation frankly is much better, shorter and up to the point with no excesses.

Timequest gives a lot of information, equations that are not relevant at field. In fact I don't want to know how they internally calculate slack but I need to know basics of managing negative slack. There are several equations for computing slack but that is for the tooland I don't need to know that but discrepancies are really painful and the more one reads timequest the more pain one gets!