Pessimism
A tendency to always think negatively is called pessimism. A pessimistic person mostly focuses on unfavourable or negative aspects of any situation, they hardly consider positive things of any situation.
Pessimism may refer to a determination on the darker side of a situation, to the presumption of a negative outcome, or a hopeless attitude towards the future.
Generally pessimism doesn’t develop by choice. Some people have genetically negative approaches towards life. People who are pessimistic may also be more likely to notice or predict potential risks and are mostly anxious or worried.
Some individuals may also be more prone to pessimistic influence, meaning they are more likely to overestimate the probability of a negative outcome. However, there is also a benefit of pessimism, the tendency to anticipate negative outcomes may lead people to take more precautions, which may in turn lead to improved health and risk free decisions.