Quite some time ago, my aunt and uncle were staying with us and the morning they were leaving I was the only early bird to rise with my aunt and uncle. As part of my morning routine, I started putting the dishes from the dishwasher away and my aunt says, "You're just like your uncle. It's good that you're willing to put the dishes away, but you're clanging them around so loud you'll wake up the whole house." I appeased her and began to place the dishes in a kinder and gentler manner. Since that visit, there have been a few mornings where I think of that incident, and I think my poor uncle. He never gets credit for putting away the dishes quietly. If he does them quietly, my aunt doesn't wake up, so she never thinks that he did it quietly; however, every time he makes enough noise to wake her up, he probably gets nagged when she stumbles out of bed.

In providing customer service, there are several examples where you don't get credit for an activity, behavior, or outcome when you do it right, but if you do it wrong, it's a huge take away.

CLEANLINESS > If the store is clean, customers won't go tell their friends, "You should definitely shop there. It was so clean." But if the store is dirty, you can bet that will get noticed.
POLITENESS > Being polite is expected = no credit. Being rude = big takeaway.
ACCURACY > Get my order right, and I simply go on about my business. Get it wrong, and I'll tell everyone for the next week.
PUNCTUALITY > It's only when people are late that we start to notice.

What are some other taken-for-granted service behaviors that we don't get credit for, but have a heavy penalty when they are missed?