I thank God that He made me a cheerful person that sometimes I can still laugh even if something is bothering me. I easily get stressed in working few hours and that is how I learned to unwind myself by focusing on things that are good and worth smiling or laughing.
A cheerful heart is vital in my life. Laughter used to be my therapy. My room mate and I used to laugh out loud like crazy until it we were worn out, but the result was really wonderful. It gave us a healthy heart, body and mind.
There is a deeper, abiding joy for those who trust the Lord that is based on much more than frivolity and circumstances. It is a joy based on God's salvation. He has provided forgiveness of sin and a restored relationship with Himself through Jesus Christ. That gives us a deep joy which circumstances cannot shake because joy comes from the Lord who lives in us, not from what's happening around us.
"A cheerful heart is good medicine, but a crushed spirit dries up the bones." (Proverbs 17:22 NIV)