Their parents taught them to worry
If a parent was over protective then the child might conclude that the world is unsafe and that anything wrong can happen. When that child grows up he will very likely become an adult who worries often.
They have low tolerance for uncertainty
People who can’t handle uncertainty are very likely to worry more often than others. Because those people can’t stand living without direct answers they keep worrying until they get them.
They don’t believe much in their plans
People who have solid faith in their plans can hardly worry. When a person starts to doubt his plans then he will start to worry.
They are negative thinkers
People who think negatively are more likely to worry than those who don’t. A negative thinker will always imagine bad scenarios in his mind and as a result he might worry.
Too emotionally attached to something
When a person becomes to emotionally attached to something then he will worry often because he won’t be able to imagine the possibility of losing that thing. If a person desperately wants a certain job then he will very likely worry a lot before the job interview result is announced. (See 20 Signs That You Are Emotionally Sensitive)
They keep checking the numbers
People who keep checking their emails, stock market prices or the news are very likely to come across triggers that make them worry. A person who keeps getting lots of external inputs might come across something that makes him worry.
Low self esteem
In some cases worrying can happen because of low self esteem. If a person’t isn’t very sure of himself then he might start to worry about his performance and the results he can get.
They Are control freaks
People who always want to be in control are very likely to worry more often. Because those people experience loss of control during certain times they quickly start worrying until they feel in control once again.
The mind thinks it’s helping
When the mind sends worrying signals to a person it believes that it’s helping him by reminding him of his problems. The minds of the ones who worry often might over do it while just believing that its helping. (See How your mind can make you sick?)
Poor past experiences
If a person has been through very bad past experiences then he is very likely to become a worrier if those experiences affected him badly. In such a case the person will worry about the repetition of such events.
Poor coping strategies
When a person fails to handle problems well that they affect his well being he will very likely become a worrier because of not wanting similar problems to happen to him again. People who handle their problems well aren’t likely to worry often because they believe they can handle them.
They don’t take serious actions
Sometimes the mind is right when it sends emotions of worrying. If a person doesn’t take actions to solve his problems then his mind might send him such emotions to motivate him to get things done.
They have nothing to believe in or have weak faith
People who have faith in any kind of super power usually worry less than those who don’t. People who believe in luck, Karma, the universe or God are less likely to worry than those who don’t if their beliefs were powerful enough.
They watched their parents worry often
Children who watch their parents worry often usually become worriers when they grow up. Because the child usually learns such patterns of thinking from his parent he can become a warrior if his parents worry often.