I was reading a book by Professor Richard Wiseman (nice name for a professor) where he quotes a study by Ellen Langer of Harvard University.
Half of the residents in a nursing home were given a houseplant and asked to look after it.
The other half were given an identical plant but told that the staff would take responsibility for it.
Six months later, the group who were taking care of their plant were significantly more happy, healthy and active than the other group. Even more impactful, 30% of the residents who had not cared for their plant had died, compared to 15% of the group who were taking care of the plant.