Researchers found that having a positive attitude and a sense of humor could play a role in living a longer, healthier life,according to yahoo health.

They developed a questionnaire designed to identify certain genetically-based personality traits and used it to assess 243 Ashkenazi Jewish adults between 95 and 107 years of age. The investigators chose this population because their genetic similarity would make it easier to account for genetic differences in personality.

"The results indicated they had two things -- a positive attitude for life, meaning they are optimistic, easygoing, extraverted, laughed more and expressed emotions rather than bottling them up," said Dr. Nil Barzilai, a study co-author and director of the Albert Einstein College of Medicine's Institute for Aging Research.

How to keep positive attitude ?

Be careful what you watch on television. Watching the news all day can make you lose your positive attitude because most of the stories that they air either make you want to scream or cry. Try a comedy instead you will feel better.
Laugh often and keep a good sense of humor. We tend to be too serious and let even the slightest problem enrage and irritate us.
Find a positive way to release some of the anger you may be holding in. Begin to journal or seek a counselor you can confide in. Start a regular exercise program where you can release some of your tension
Every day write down a list of at least three positive things that happened that day. This will force you to think positively and will start to teach your brain to think in that direction.
Find a hobby that you love. A hobby will help you set some time aside each week to focus solely on yourself. Be sure to choose something you really enjoy doing and that it makes you feel good about yourself when doing it.
Use positive affirmation every day. This can be difficult if you are not used to thinking positively. You must try to catch yourself being negative and find a way to turn the situation into a positive.
A study, based on a survey of almost 8,000 men and women aged over 50, shows that regular users of social-networking sites are almost a third less likely to be diagnosed with depression compared with non-users.