Humour is whatever a person finds funny. Not everyone finds the same things funny.
Laughter is how your body responds when you find something funny.
People who laugh are pleasant to be with; pull a long face all day, and you will soon notice that others try to keep out of your way.

What happens when you laugh?
You see your problems differently, sometimes they go away
You feel better about yourself and colleagues
It helps your heart beat easier and blood run smoother to your lungs
Your body feels more relaxed and good all over.

Want a simple way to boost the spirits of your guests, then you need to make them laugh and smile as much as possible. As simple as it sounds, laughing is beneficial to the cardiovascular, respiratory, muscular, and central nervous system. Research also shows that laughing can boost the immune system helping the body to fight colds, stay disease fee and helps people with type 2 diabetes process sugar after a meal.

You’d be amazed at how much better your job and the world looks through smiling eyes.
Laughter is not only good for the soul, it appears to be pretty good for the body as well.
During a laugh, the throat goes into uncoordinated spasms, sending blasts of air out of the mouth at 110 kmh. The body starts pumping adrenaline; the heart rate increases; the brain release endorphins and enkephalins, natural painkillers.

When a person laughs, and endorphins are released, they make a person feel good, relieving stress and indirectly reducing one's risks of suffering a heart attack and other health problems.
The lungs pump out carbon dioxide, the eyes cleanse themselves with tears, muscles relax and lose their tenseness.

The exercise value of laughter is so great that William Fry, a psychiatrist at the Stanford University School of Medicine claimed that laughing 100 times a day is the equivalent of 10 minutes of strenuous rowing.” - Orlando Sentinel

From “Science of Laughter” Discovery Health
“By the time a child reaches nursery school, they will laugh 300 times a day. Adults laugh an average 17 times a day.”

When we are immersed in a good belly laugh, we tend to be so fully present in the moment that we forget about anything and everything else. Children are more fully present in the moment at hand because they aren't consumed with what tomorrow "may" bring or with the regrets of yesterday. I guess we could say that, for many, life is a "serious" problem until they learn how to lighten up a bit.

In closing a light hearted joke:

A crow was sitting on a tree, doing nothing all day.
A small rabbit saw the crow, and asked him, "Can I also sit like you and do nothing all day long?"
The crow answered: "Sure, why not."
So, the rabbit sat on the ground below the crow, and did nothing.
All of a sudden, a fox appeared, jumped on the rabbit and ate it.

Management Lesson: To be sitting and doing nothing, you must be very high up.