Unlike a vegetarian, who simply doesn’t eat any kind of meat, veganism means that you don’t eat any animal products at all—so on top of eliminating steak, chicken and turkey from your diet, you also stop eating foods like eggs, cheese, butter and more, or replace those with a vegan substitute.

However, some people choose to embrace a vegan diet without really knowing what’s going in their food. Case and point: A Subway worker who took a vegan girl’s sandwich order. He wrote about his experience in a now viral Reddit post.

When the girl began to order, the girl informed him she was vegan and asked him to replace his gloves since he was handling meat that she wasn’t going to eat.

“I did that, no problem, perfectly reasonable request,” he explained. “I get her bread, toast it and put all the veggies she wants on it, I start to wrap up her sandwich when she says, ‘can I get some mayo?’”

Most people know that mayo contains eggs in it—but apparently, a vegan herself had no idea that she was asking for a condiment containing an animal product.

“I look at her, she’s looking at me, I pick up the mayo, I’m waiting for her to be like haha jk.,” the man wrote. “Nothing.”

After asking her if she knew that mayo contained eggs, “THIS. GIRL. JUST. STOOD. THERE. SILENT,” the man noted in his post.

“She stood there for a second,” he wrote, then relaying their dialogue: V: ‘N-no it doesn’t, I get mayo every time, are you sure?’ ‘Me: ‘Yes ma’am, mayo has egg whites in it.’”

“I felt so horrible, she stood there with such a distraught and defeated face, I had shattered this poor girl’s world,” he said.

With lots of other people waiting in line, the man knew he had to get her out line. “’Would you like the mayo on it ma’am?’” he asked her to which she responded, “Sure, go ahead.”

“She sounded so done, so defeated,” he said. “So I gave her her mayo, wrapped her sandwich up and charged her for her sandwich, she was silent the whole time. She took her sandwich and started walking out.”

When he told her to have a nice day, the (ex) vegan woman just responded with a sigh, “yeah, I’ll try,” and walked out.

“And that’s the story of how I taught a vegan that mayonnaise is, in fact, not vegan,” he said.

Eek!

Did you know that mayonnaise had eggs in it? What would you have done in this man’s position?