In the early years I had no choice but to buy a car on hire purchase. There was something very satisfying about making the final payment. Maybe the feeling you could now do what you wish with the object is the feeling of ownership.
By some unfortunate folks, ownership is fueled by jealousy and 'keeping up with the joneses'. Yet others, no doubt, enjoy the knowledge that it is not owned by anybody else.
I suspect there is also a primitive influence of owning things to impress a potential mate.