This verse in the Bible is a great suggestion.  But for more reasons than you would expect.  It is claimed by many practitioners that people that have a pleasant disposition are healthier.  Further, it is mentioned people that believe in Deity and pray accordingly, have quicker healing time following surgery.

We all like to be around folks that are happy.  They will often even uplift us. I suppose life has many challenges and struggles but we don't have to express or exhibit our problems to all in which we associate. It's nice to have a friend, relative or neighbor to lend a listening ear periodically or as needed. But you may find the listening person not being around much if the negative thoughts are a constant habit.  "A friend in need is a friend indeed".

Sometimes listening to all of the complaints and gripes from a person, we feel not only like a sounding board but finally the issues become our problem as well.  A "hospice heart" or a magnanimous quality in a caring individual is unique and not everyone can do this.  Choose your "sounding boards" carefully.  Or better yet, don't be down on everything and everybody in life.  Seek experiences that make you happy and realize people will like you because of your pleasant attitude.

A wonderful book entitled, "Of Monkeys and Dragons" details how negative words and feelings can even create or harbor cancer.  The nurse that wrote this book was quite scientific in her explanations and experiences.  She wrote about many case studies where negative influences were removed and cancer was healed.  Many households that have experienced cancer never let the "c" word enter into the home again.  This nurse talks of the Spirit without ever mentioning any specific religion.  The Spirit is real and often the so called "grounding" is found in prayer, yoga, tai chi, or meditation.  Too much of today's life takes us away from emotions, feelings, and sensitivity.  Grounding must be found to be a truly happy person. 

It behooves all of us to find our "happy place" as we need it.  All too often, we don't take time to vacation or to divert from our daily activities.  Vacations don't have to be expensive.  Sometimes an extravagant vacation is more hassle than what it is worth.  The travel problems driving long distances or airline difficulties, high prices, checking into hotels, inclimate weather, illness, accidents, and the energy exerted may not be worth the trouble.  You may almost feel like you need a vacation from your vacation.  A "staycation" is often a good choice.  Shorter driving distances, less cost, sleeping in your own bed, no anxiety of leaving your home, and much more may be the better option.  At least you're still diverting your day to day routine for a change for a while.

Ultimately, everyone can find some kind of joy in life.  Many physiological elements of the body can be improved through finding happiness doing something.  Blood pressure can be controlled with the parasympathetic brain overriding the sympathetic when you know how.  Depression and anxiety can be overcome with proper OTC supplements, counselling, and seeking ways of improvement.  With many, this may be a lifelong endeavor but you will be rewarded.  So many health issues will improve by being of good cheer!