Some years ago (2014) my friends and I did a trip to New York City, during which we were having meals in many restaurants and giving tips to the waiters, the way it's done in the USA.
However, later on, we visited a popular skyscraper building and we paid for the tickets in cash to the woman who was selling those. When she was taking the money she said something like: "Ok, you're six people, it's $138 in total and I'm going to take $12 in tip." I had paid with $150 so she basically took the whole change.
Even if I didn't realize it at the very beginning, I felt annoyed later on when we were already in the lift. In my country it's not usual to give tips and we do it to show gratitude when the service in some restaurant goes beyond the standard. I understand that in the USA it works in a different way, but I think you must do some kind of extra effort apart from grabbing some tickets for the customers. This situation isn't included in the table given in this answer.
Is this situation common? Or did the woman take advantage of us for being foreigners?