I think you make a great point. I've been involved in sales and marketing for many years, and the one thing that all those years taught me was to think like a buyer when trying t sell something.
So many don't look at things from a buyers perspective, they only consider things from a sellers perspective, and as strange as it may sound to many, the two aren't the same.
It all comes down to knowing your demographic in sales, no matter what you are selling. Understand your customer extremely well, and you're well on the way to making a sale.
I digress a little, but to get back on your point about feedback left. It's one of those little 1% areas that people lose sight of, but if you tick off a lot of those little 1 percenters, you get a lot closer to ticking off 100%
I always leave personal feedback for customers, and I leave it the same time as payment is received. I don't wait to see what they are going to do, that's something I have no control over anyway.
What I also do is respond to all of the feedback received. This is an area that I thing many ignore. They feel that the feedback is in, alls good, time to move on.
Don't just take the time to respond to negs, show you provide real customer service by following up positive feedbacks with a simply thank you, and a hope to do business with you again. Even if that person doesn't see your response to them, the next customer looking through your feedback will, and that's where that little 1 percenter can score you a sale!