Rule number one of being a customer anywhere is that it usually pays to be nice. You never know what employees are getting up to behind the scenes, and bad manners may well stop you from getting the best service.
This is certainly the case at the McDonald's that @nnennaaaaa6 works at, as she revealed all on TikTok when dealing with a rude customer on the drive thru. After they ordered ice cream, she decided to tamper with it to get her revenge.
Her actions caused controversy in the comments, with some unimpressed with her behavior and others expressing complete understanding for her motive. In fairness, the most surprising thing here is that the ice cream machine works in the first place.