the importance of keeping good mood

In the modern society,people do not feel happy anymore. because they are suffering from different kinds of pressure,like education pressure,career pressure,family pressure,and so on,the shinning smile on people's face are disappearing ,so it's time to keep good mood.
in fact,keeping good mood affect our healthy situation,i'm not kidding,scientist proves that good mood is the key point that make your life longer.and bad mood easily leads to some sickness.like cancer,those patients who hold optimistic attitude about their illness,they have larger opportunity than those who hold pesmistic attitude.except that,good mood can help us a lot when we face up with the diffculities in front of us,.good mood is so useful,why not keeping good mood.
in conclusion,i think good mood is a neccessary part of our daily life,he is our friendly company,our lowyal listener.we all like it

The Importance of Staying in a Good Mood
In modern society, people do not feel happy anymore because they are suffering from much pressure related to their education, their career, their family, and so on. The shining smiles on peoples' faces are dissapearing, so it's a good time for a good mood. 
In fact, being in a good mood will make you healthier. I'm not kidding! Scientists have proved that a positive attitude is the key to living longer, while a bad mood often leads to sicknesses, like cancer. Those patients who maintain an optimistic attitude about their illness have a better chance (to survive) than those who have a pessimistic attitude. A good mood can help us a lot when we have to face the difficulties in front of us. If a good mood is so useful, why not stay in one all the time?
In conclusion, I think a good mood is a necessary part of our daily life. It is our friendly company, our loyal listener. What's not to like?

1) Pressure is not a countable noun, so we have MUCH pressure, but from MANY different sources
2) Nice poetical flourish in the conclusion, personifying the good mood as "he". If you are using a poetical mood, you can bend the normal rules of grammar, but it must be good poetry. 
3) I like ending these journal entries with a rhetorical question. 
Thanks for putting me in a good mood!