I voted that it doesn't affect me at all.
That doesn't mean that sales don't influence my buying habits, they frequently do. However if I want something I'm going to buy it, whether it's on sale or not. If it goes on sale at some later time (even that afternoon) I really don't care. I paid what I felt was a fair price or I would not have purchased the item.
Marketing is important for anyone selling goods and sales are an essential marketing tool. You will always have people who will think/say "If I had waited...." or "You could have said you were having a sale....." and if they decide not to purchase from you again for that reason you can't control that. IMHO, the benefits of having a sale far outweigh the complaints, chief among which is attracting new customers. If that weren't true no one would have sales, right? You'll never be able to please everyone and IMHO other than providing good products and good customer service there is no reason to stress about it.
If we had the key to what pleased everyone all the time we'd all be rich.