Dr Barbara Plester is an expert on workplace humour and when it's a good or bad idea. The University of Auckland professor in management and international business has spent 14 years studying the topic and her latest book has been written with fellow academic Kerr Inkson. She explains that like many things, what's appropriate and what's not has changed in recent times. Dr Plester also embedded herself in different companies to observe all types of humour and how it affected employees as well as their superiors. That's all been worked into the book "Laugh Out Loud, A User's Guide to Workplace Humour".