Re: Some advice
Basically you need to - is to understand your customer.
A customer walked in and
*you never see the customer before, just ask him/her - "Sir,can i help/assist you"
*you do see him a few time before, try to remember what did you or he do, make him happy
many others way to know and how to deal with the customer - this should be company-training.
If the customer act and talk not the same as other, follow his style.
Note: First Impression IS very important. Greet with EYE to eye contact (with a simple smile), do not look away. For me this is my way to know people. Face to Face is the FIRST Contact. If had contact with the customer, say over the phone; in person - do the eye to eye technique. I read this somewhere very long time ago. It works for me.
Whether he is your customer or your friend's friend, both is the same.
One good example in this Naruto manga Chapter 492.
See what and how Bee greet, but unfortunately Naruto did not response in the same way. This offended Bee.
About this issue, Kishi had given one useful HINT.
Remember when all the tailed-beast use the fist to fist contact; they gave part of their chakra to Naruto.
Same as where Kurama give his chakra to Kakashi & Guy.
Also when Naruto had finished taking control of some Kurama's chakra, Bee and Him did the fist to fist contact. Both understand what had happened, which make Yamato angry.
And The fight between Sasuke and Naruto, Naruto then said something, which only both understood.