Different state and role of people

From a customer , to a service crew and now a customer + service crew.
On the above 3 different role of a person to a shop . Which will be the best role ?

Service crew ?
To serve different type of customers who went into the shop and stay there whole days observing how different people will have their different personality . Although not happy or angry also , they need to stay happy and serve their customer with excellence service .

Customer + service crew ?
A win-win situation that when you are a customer , you spent money . But , when u work , you got back de money from your boss . In short , its also a way of exchanging system . You get the things you want by providing service for them .

Customer ?
The most easy and simple type of people among this 3 . What a customer need to do ?
Just go to into the shop and ask for the service he/she need . Satisfied o not , they pay the amount charged . But , they can anytime choose to made a complain if they wish to . Customer mostly only know how to complain and forgot bout compliment . They feel that customer is always right . They should be serve as a king although they din pay any service charge at all .

In every shop/business , there will be customer and worker . Today you may be customer at shop A but , tmr you maybe giving service to others . Its just like a circle . What you did to others , will be happened on you in a day .

Obviously , everyone will agree to me that being a customer will be the best . Easy and simple . But , you may lose de fun of meeting people from diffrent lifestyle .
Some customer will be really bad that you feel to scold them when you serve them . And some may be very good till you may even try to serve them the best you can .
Either its a good o bad people , its your customer and you need to serve them as they step into your shop . That's all .