Spending Money
Apparently, there is a region in the brain that is unpleasantly stimulated when spending money, known as the insula. This stimulation makes it difficult for us to spend money. However, this region is not equally sensitive in everyone...
In more frugal individuals, it quickly responds, while in more generous individuals, there is less activity in that region when spending money.
Both overspending and underspending are trainable, and the training effect can be observed in CT scans of insular cortex activity.
The unpleasant stimulation works through the same receptors as physical pain; those who take over-the-counter pain relievers such as ibuprofen, aspirin, or paracetamol also suffer less from the loss of money.

