How to handle unwelcome comments about my daughter’s facial expressions?

My four-year old daughter is freaking adorable. She loves to dress up "fancy", has a cherub face, and has always been small for her age. She has a bubbly (and strong!) personality and finds the humor in everything. However, there's no other way to describe it: my daughter has an RBF. I have to confess, it’s often amusing because she’s always dressed to the nines, but often looks ready to fight someone—even when she’s in a fantastic mood—which is funny on someone so tiny. The problem is, I don't know how to handle the unsolicited and unwelcome comments about it.

Since infancy, we've had everyone from close friends to complete strangers make comments about her default facial expression, mostly variations that my daughter looks "mean" ("oh! I'm getting mean-mugged!" "I wouldn't want to cross you!" "Whatever I did, I'm sorry - don't be mad” or “Watch out, she’s not playing around!”) I usually just ignore it, especially since I truly believe these folks (mostly older) are just trying to be “funny” and they have no idea that these comments are made about her monthly, if not more often. If it’s especially egregious or my daughter notices, I tell her that the person shouldn’t have said that because it isn’t true or remind her that she is so nice.

However, I’ve come to realize that I really need to find a way to address these comments head on. Earlier today we were at the local Christmas market and someone made a comment that finally set me off. We had just arrived and I was pushing my daughter and my son (7) in their wagon. They were bundled from head to toe in winter gear and covered with blankets. We were excited to see the lights, meet Santa, and just have a fun family trip together.

An older gentleman walked by us and made a joke about how if the wagon was just a little bit bigger, he’d get in too. I played along and said there’s enough room, so if he wanted to warm up for a while he could hop on in. He laughed and said “well, I would, but this one here sure looks mean and I doubt she’d let me.” Sure enough, I look over and my daughter looks mad, but I knew she wasn’t. It was her normal resting face, mixed with being too cold. She was actually extremely excited about being at the Christmas market.

Again, in isolation, it’s not that bad, (though it’s entirely unnecessary for anyone, let alone a stranger, to comment on my daughter’s demeanor or accuse her of looking “mean”), but I cannot imagine how it made my daughter feel, especially since someone had made a similar comment only days earlier. In this instance, I walked away without saying anything else to him and told my daughter that people just recognize that she looks strong and should find a nicer way to say it.

With that context, I need to find a way to defend my daughter without embarrassing her or making her feel like she’s doing anything wrong. I’ve thought about immediately asking “are you really suggesting my daughter should ‘smile more’?” but I’m worried that’s a bit too confrontational. I also don’t want my daughter to think she has to look happy all the time to be considered pleasant, especially since my son has a very similar resting face, but has NEVER gotten any comments made about it. I’d love any advice!