Double Standards

Sometime I just couldn't understand what is causing people having double standard on almost everything...treatment, pricing on goods, courtesy etc.

Just because you happened to live in a particular street doesn't mean that you are rich or poor as the others in the same surroundings. But, what I have learned from the last few days' encounter with some merchants such as the curtains vendor, locksmiths, plumber etc. First reaction from them is "Wah! you live there ahh? Very expensive place hoh..." then suddenly you found out that the prices quoted are slightly bummed upwards. Why is this? Just because you live in a decent terrace house on a more affluent area, and you have to pay more for almost everything?

Still couldn't figure out the logics behind it. I think I should experiment putting an address in those less significant places ... once the rates and pricing has been agreed...quickly say...oh I forgot, the address I have given is my friend's place...my actual address is XYZ....see if they can find an excuse to change the price.