Happened to me a few times, but it is buried so deep I cannot remember the things they said. Don’t take it personally, think about it with empathy - what kind of a sad life must someone have to feel the need to make a stranger feel bad, too? Pity them. The people I met who tend to be mean to/talk bad about strangers because of outward appearances often enough had some serious troubles with their own lifes and especially self-esteem. It made them feel superior to talk someone else down. Often enough I think they are just jealous or misogynous. How old was this stranger? Maybe they would like to be 30 again to live life differently. If they were younger - maybe they figured you had the button because someone gifted it to you, or you had a party just for you, and this person does not have any friends to party. Whatever it is - nothing’s wrong with you, it’s the person who actively chose to spend their time - even if just a short moment - to make some stranger feel bad, who has a problem. Don’t let your birthday memories be shadowed by this and enjoy your coffee.