This trend of small business owners putting customers in their place for not greeting them before asking questions is one that is really burning up my insides LOL..... Customers are not required to do anything but follow your policies and make a purchase if they want to. Literally the definition of the word customer is, " a person or organization that buys goods or services from a store or business." and every time I see things like, "customers need to be better customers," I die a little more, it just shows a lack of professional knowledge.
The thing about business ownership is, it forces you into a position of leadership and clearly so many are just not ready for that role. I believe everyone can be a leader but they have to work at it. If everyone could be a business owner they would right? There is nothing wrong with just being the consumer. Leaders should influence behaviors and be able to control their emotions. For example, If your customer/potential customer starts off a conversation with a question , and you prefer a greeting instead of try and check someone who could be paying you, simply greet them and then proceed with what you have to say. You set the tone in leadership not others. Check out my book to learn more about how to leverage your natural leadership style when showing up for your customers.
Another thing, social media, chat, and text are all informal methods of communication. Informal interactions do NOT require a proper greeting.