An elderly, wheelchair bound man and woman would meet behind the potted palms for some hanky panky in the nursing home lounge.
One day, the elderly woman looked around for her partner and he was nowhere to be found. She scoped out the room and found him behind the potted palms WITH ANOTHER WOMAN!
Tearfully, she wheeled over to them and confronted him- asking, "What does SHE have that I dooon't???"
The elderly man thought about it for a moment and replied, "Parkinsons!"