I have a 2006 Grand Prix and the automatic transmission shifts a little hard from 1st into 2nd. Fluid levels are fine and clean.

Sometimes a Grand Prix will do this after the transmission memory resets. You probably had it at one time when you had to give it gas at start up then it stalled. At that moment, the transmission resets because it acts like the battery was dead. If that's what happened, then drive it through your normal habits so that it regains normal memory and it should go away or relearn itself. Second tip: I have had Grand Prixs in the past that shifted a little hard after 15 minutes of driving. I don't know what the repair could be but it doesn't harm the transmission long term. Good luck!

Take it in and get it serviced. Transmission problems rarely go away or get better with age. Usually they just become grossly expensive. A bit of preventative maintenance now could save you thousands in a few weeks, if its not already too late.