Haggling over prices when you have tens of billions in assets

Trying to haggle over the price of vegetables at the market is a kind of obsession or a sickness, isn't it?
If someone has tens of billions in assets, even if they get vegetables for free,
it doesn't actually provide them with any real benefit.
On the other hand, that few hundred won margin for the merchant is directly linked to their livelihood.
I wonder if they just feel a sense of fun or euphoria from the act of haggling itself.