Humour is by far the most significant activity of the human brain. - Edward de Bono

Vertical thinking is selection by exclusion. One works within a frame of reference and throws out what is not relevant. With lateral thinking one realizes that a pattern cannot be restructured from within itself but only as the result of some outside influence. So one welcomes outside influences for their provocative action. The more irrelevant such influences are the more chance there is of altering the established pattern. To look only for things that are relevant means perpetuating the current pattern.

Unhappiness is best defined as the difference between our talents and our expectations.

The concept of logical thinking is selection and this is brought about by the processes of acceptance and rejection. Rejection is the basis of logical thinking.