The word "Humour" and "Humor" means the same, ofcourse with a slight difference in spellings. This is because "Humour" is a British word and "Humor" is an American. Anyways, it doesn't matter whether it's "Humour" or Humor", it's unlikely to offend you.
Life is hard. There are many difficulties and challenges that you have to face in your every day life. At times, life can be too overwhelming and intense that you get emotionally burn out. This is why you need to keep a better balance in your life against stress, disappointments, pain, anger, sadness, disagreements, etc. A "good laugh" can do a wonder! It can give you courage and strength to survive even in most difficult of times. A good laugh is a way of dealing with stress and pressure in life. It can bring your body and mind back into balance and create an optimistic outlook in you. A good laugh can lighten your burden, brightene your day, diminish your pain and boost your health psychologically and physically.
The one serious conviction that a man should have is that nothing is to be taken too seriously -- Nicholas Murray Butler