There are certain personality traits which are more useful than others and that can also depend on the situation. The ability to always make someone laugh can be considered a useful personality traits as it can make you a lot of friends, but if you are stranded on a deserted island, your sense of humor may not be helpful to you.
Overall, my ability to think critically and use logic to understand and evaluate information has definitely been the most useful in my life. Being able to think critically can help you to make the right decisions even in the face of difficulties or adversities.