Not all animals can smile. The human smile comes about from psychological responses and triggers hormonal/chemical changes in the body…its not just a smile.
We don’t have to be serious to learn. The chemistry of fun has been found to stimulate the human mind in positive ways that increase alertness and open a person to new experience. This is a great facilitator for management and team building programs.
Fun is a glue to human inter-activity. Programs with very serious productive intent have their goals enhanced no matter what they are if the participants are finding the experience fun and they are sharing that with others.