In my tenure of working for 8 years in software industry and 3 years in transportation industry, I heard about the slogan Customer is God (Grahak Devo Bhava) hundreds of times. But recently I realised that it is not true, infact it is a slogan generated by greedy minds to attract more customers, more business and there by more money.
Customer can never be God for the simple reason that God has given everything for free e.g. Air is free, Water is free, Earth does not charge anything to multiply grains whereas the relation with the customer is always of give and take. We give some product or service to customer and we get money in return. So all those people who teach Customer is God theory are either ignorant or greedy.
Lot of people in service industry realise this fact daily. Sometimes customers make unreasonable, unrespectful demands and such customers many times get unreasonable and unrespectful responses.
Customer should be treated as a customer and not as God, giving Godly status to customer would only give rise to corruption and misery.