Twenty percent. Except in cases of fire, injury, or severe abuse, this is the correct percentage to tip your server. The recent plight of a Gothamist tipster (ha) has prompted us to clarify our tipping policy.

The names and locations have been redacted to protect the innocent:

I have been living in NYC for about a year and this is the second time I have encountered being overcharged at a restaurant when using a credit card. First my roommate was overcharged at a bar by just 50 cents but then today I discovered I was overcharged at [RESTAURANT] in [NYC NEIGHBORHOOD] by $8.99. The waiter had been very rude, so I left him only a 10% tip and a note on the tip politely explaining why I thought he was rude. I took a picture of the receipt, as I always do since my roommate got overcharged, and low and behold he overcharged me by $8.99, which ultimately gave himself a 20% tip!

The photo of the receipt shows a bill of $32.12 and $3.00 gratuity, for a total of $35.12. Below the signature line is the phrase, "very rude." The phrase is also underlined. The tipster was ultimately charged $44.11, according to a screenshot of the credit card statement.

This is wrong. The server may have made an honest mistake. Any service employee who has used Aloha or POS or Micros or any of the other hopelessly complicated ("OK so Margaritas are under 'Sauces' and press Outdoor/Add'l Table to void a drink check but to void a meal check you…") brightly colored "idiot proof" computer programs knows it is perpetually haunted by the kind of user error that is inevitable after a shift (or two, back to back) of waiting tables.

Or he could have illegally juiced his tip to nearly 40%. This strikes us as blatantly stupid, but it's certainly possible.

We asked the tipster what she meant by "very rude."

I wrote he is rude because I never like to leave a bad tip without explaining why.  He did nothing offensive per-say. His general mannerism was not friendly. He left us waiting for long amounts of time, just to get water even, he would make facial expressions as if we were disturbing him, he would start walking away during a conversation. He was unpleasant.

What if your boss docked you $6 every time you sighed loudly? If your "mannerisms" at the microwave are less than convivial, do you deserve a full day's pay? Should a tardy spreadsheet shrink your bimonthly direct deposit?

What if your base wage was $5/hour?

These are the thoughts that you should ponder before you consider tossing the Bic Pen of Damocles down on the receipt of the Mediocre Server.

Oftentimes, the Mediocre Server isn't always Mediocre! They are merely having a rough day, or week, or month. Depriving them money for services rendered deprives them of sanity and deprives you of dignity. When you tip less than 20%, you're not forcing the server to engage in didactic introspection, you're simply being cruel.

Cruel not just towards the server, but to the busboys, runners, and other servers who often pool tips with each other to scrape together a living bringing you food.

If the service or your meal was truly terrible (fire, injury, severe abuse, etc.), tell a manager. You might even get a free drink, or a free meal. Tip 20% on whatever the check would have been before you complained.