It is a very good topic. As a Chinese, we have our way to do things. It is seemed normal that you pick the vege you buy since you paied for them. In China, who does not pick their food when they go shopping. it is all depend on the situation. Here there is not a lot of people to pick the vege upsidedown to find the best of all. Here, in general ( I am not talking about indevidual case) , the culture setting is different. We are not talking about which one is better or worse. Just we are here. It is for our own good not to offand others and respect their settings ( or rules). This way every body is happy. After all we are the new comers. Do not just focus on the little sport. We are here and we want to be accepted ( no offense). Too bad I can not type Chinese. Hopefully it will make sense.
Find out what is better way of doing things and do it. This sound easy. You have to evaluate the thing you are doing. Then it is the value you have determinds how you do them.