The serotonin is intercellular messenger in brain to control your mind. It's said the lack of serotonin drive you mad and angry. Recently, young people tend to be mad and angry so easily.
But, This topic said middle and aged persons are also same.. Oh.. Everyone is mad??(laugh) For sure, Sometimes, I also get grumpy.. How can I deal with that mind?? Stress-relieving?? How can I do that? sleep!?
laugh!? 
sports?!
... But, I think it's the stopgap relief, not the real solution.
http://news.goo.ne.jp/article/mainichi/life/20071120dde012040002000c.html
But, This topic said middle and aged persons are also same.. Oh.. Everyone is mad??(laugh) For sure, Sometimes, I also get grumpy.. How can I deal with that mind?? Stress-relieving?? How can I do that? sleep!? laugh!? sports?!... But, I think it's the stopgap relief, not the real solution.http://news.goo.ne.jp/article/mainichi/life/20071120dde012040002000c.html