Parked on an incline. Had trouble getting out of "park." Am I liable to get stuck in park one day?

[Dennis S]

2002 Buick Park Avenue. I parked with the front end higher than the rear in a driveway. When I tried to put the car into reverse, I couldn't get out of park for about a minute of struggling with the gear shift arm. Is this liable to be a common thing while parking on inclines?