Pet Peeve

I hate stupid questions. I hate it when people follow a script without thinking of what they are saying. For instance, I was in a store today. I could not find what I was looking for, I assumed they had discontinued the product and I found something that I hope will be a suitable alternate. Never once did someone in the store ask if I needed help finding something. That does not annoy me because most often when a salesperson asks me I am just looking, and therefore as a rule I prefer not to be harassed while looking. When I made it to the counter the cashier asked if I had found everything ok. What a weird question. This question always annoys me, but in situations when one has been aimlessly looking for a long time, it is especially annoying. What kind of answer to give. Yes, I found what I brought to the register. No, I did not find the things I was actually looking for and did not bring to the register. Anyway, I told her the truth. I told her I did not find the item for which I was looking. Did she ask me what that item was? No. Did she offer to assist me? No. Did she ignore my answer to her question and check me out? Yes.

Why do they ask those questions? What does it help?