There could be several reasons why people sit in their car when someone is waiting for their parking spot:
Finishing tasks: Sometimes, people may be busy finishing a task like sending a text message, setting the GPS, or making a phone call before they start driving again.
Organizing belongings: People might need some time to organize their belongings or shopping items inside the car before leaving the parking spot.
Resting or taking a break: After a long drive, some individuals might want to take a short break, stretch, or relax before continuing with their journey.
Avoiding confrontation: In some cases, people may not feel comfortable with a stranger waiting for their spot, and they might wait for the other driver to move on before leaving.
Waiting for someone: The person in the car might be waiting for their friend or family member who has gone to do a quick errand or use the restroom.
Safety concerns: Some people might prefer to wait inside the car until the person waiting for their spot has driven away, especially if the parking lot is busy or crowded.
Not noticing the waiting driver: It's possible that the driver inside the car is not aware that someone is waiting for their spot or is distracted and hasn't noticed yet.
Enjoying the air conditioning or radio: During hot weather or while listening to their favorite music, some people might prefer to stay in their car for a bit longer.
In most cases, waiting for a parking spot is a short-lived inconvenience, and it's essential to be patient and courteous to others on the road. If you find yourself waiting for a spot, give the driver inside the car a moment. If you can, try to find an alternative spot nearby or circle around until the parking space becomes available.