When you sell a product it is merely 'transactional'( you give something for a specific value- sell a notebook);
Trying to educate on nuances of nutritional value etc will not get paid mostly. Customer just 'buys'.
When you render a service it is 'transitional' ( you help a person or an institution to use the service to transition from the the present position to a better / comfortable one-nursing);
Upma served on flight is a 'service' that you 'get'.
When you sell a concept it is 'transformational' ( you make an institution to 'transform its entire orientation'-use smart boards in classrooms).
