Attention to finer details is important to overall satisfaction, and continues through the completion of a dining experience.
Relatively often when paying with cash, a server will bring change after rounding up to the next dollar. If the check were $74.65 and I paid with eighty dollars, the change would be the five bills, without the thirty-five cents difference. I know...What is the big deal? It is a trivial amount, and I admittedly leave most coins on the table. But whether from dislike of recollecting and accounting for leftover change, laziness toward counting it out initially, or encouragement by management, it is presumptuous for a server to keep the change unless it is initiated by the customer.
This technique annoys me tremendously, and can have lasting effects. Questions come to mind about the server's demeanor throughout the meal, or where else the server and even the restaurant might cut corners. The immediate result is an automatically lower tip, more than making up for the missing coins. But more than a couple of bucks on this visit, I will remember the action if I return, and avoid the server. And, if the entire dining experience were average, keeping change might easily tip me over to the decision of not returning at all.
Counting out a few coins is an easy way to avoid irritating a customer. If a restaurant accepts (or requires!) cash payment, it should be policy for servers to give change in the full amount. Or, to leave a subtly impressive parting shot, round down to the nearest dollar, and return a little extra. It will pay off, now and in the future.