Here's a tip: Get a new job

I don't know if it's as prevalent elsewhere in the world, but here in New York City, "tip cups" have become quite common. At the corner deli, at chain eating establishments, even at the bank I have seen plastic cups labeled "tips", stuffed with change and a few dollar bills, sharing counter space with cash registers and items for impulse purchases. The first problem I see here is that employees are vying for my spare money alongside Lemonhead candies and cigarette lighters with naked ladies on them. I don't know what you've been told, but in the war between friendly service and tits, tits win every time.
The real problem I have with this is that it seems basically like a license for employers to pay shit wages. Now, I don't have an ethical problem with tipping, as a whole. Any delivery person deserves a tip of some sort, being that they expend a lot of physical energy just so I can have a life-sized wax statue of Tiffany Amber-Thiessen in my living room. Mailpeople probably deserve some kind of nominal tip, so that they'll have second thoughts when the time comes to throw your important packages under the wheel of the mail truck. Same goes for plumbers, auto mechanics, and other service workers, for much the same reason. Tips in this case are basically like bribes: You didn't spit in my food, right? You didn't read my magazines in the bathroom without washing your hands before delivering them to my home? Are you sure you didn't just charge me $500 for five minutes of work and fifty cents in parts? Thank you. Here's two bucks for your trouble.
When tipping becomes a nuisance is when it starts to become more mandatory and less common sense. I'd say that restaurants were the first to employ this "gratuity", which is not unlike the thank you notes your mom made you write to Aunt Edna even though she got you the most hideous sweater again that you have no hope of ever wearing, ever. Really, I don't feel like thanking someone for simply doing their job. If your boss pays you nonsense money because the public is expected to shore you up to earning a liveable wage, then your boss needs to get run out on rails. Sometimes, a waiter goes beyond the call of duty and actually warrants a gratuity, but more often than not, you took my food order, some Mexican guy ran it out from the kitchen, and then you somehow timed your "Is everything all right?" queries to interrupt particularly engrossing bits of conversation, or to force patrons to nod with mouths stuffed full of food. Sounds to me like you simply performed your regular duties, however admirably. My only tip would be to not mention how well your band is going everytime you come by to fill up the water glasses. To afford eating here, we customers had to get real jobs, and we don't cotton to being reminded that people still have fun out there in the world.
But now, cashiers want in on this tip action, and I say it has to stop. Most of these chain store jobs have such a narrow scope that you couldn't act outside of the parameters of your job, even if you wanted to. If I went into a McDonald's and asked for a turkey dinner with all the trimmings, that would be a tip-worthy feat. But since you just cranked out another burger from your Play-Doh factory, and I had to pay two dollars for it, to boot, I don't see what you've done that should weasel another quarter out of my pocket. What you need to do is tell your boss that unless s/he can pay a wage that will sustain the lives of the company's employees, then the company itself is not sustainable. Pretty soon, robots will be performing all of our menial tasks, and they'll have no need for tips or tip cups. This is a good thing, because we're going to need all the tip cups we can get for panhandling.