Drinking warm liquids makes a person feel more generous and trusting

According to a recent study at Yale University, psychological "warmth" and physical warmth have close connections in the human brain. Researchers gave volunteers either a hot cup of coffee or a cold drink and asked them to rate how trustworthy a person looked. Far and away, the ones holding the hot beverage rated people as more reliable.

The study's findings showed that the same part of the brain handles both sensations of temperature and our ability to trust another person. Knowing that this structure, called the insular, handles both these processes means that you should probably stick to consuming cold beverages when making big decisions - so don't accept that cup of coffee when a salesman is trying to sell you a new car!
Scientists in Canada also found that the inverse effect is true - our mood can also affect how hot or cold we feel! Their study demonstrated that people who feel socially excluded are more aware of cold temperatures.

(source)