I realize as I get older, I do this more and more often. I speak up when I normally wouldn’t have. “I love those shoes!” “What a great swimsuit!”
I did learn, though, that it’s a little unnerving to have someone admire your shoes under the divider of a public bathroom, though. Wait until you are both out of the stalls.
Speak up, though! Let a woman know she made an impact on you, even if it is a small one.