Several years ago I was walking down the street to the club with a friend. He had to stop partway to put eyedrops in and explained briefly this was because of a chronic thing he was having to continually treat.
My response? "Cool!"
He looked a bit stricken, perhaps even disappointed. "Uh, not 'cool'..." he said, along with something explanatory my embarrassment blanked away.
For years, I've wished I could go back to that moment and say, "Yes! Cool! I know a couple of other people with a similar thing and now I know they're even less alone and I feel like I understand you a tiny bit better because you have to put up with this crap all the time and probably wish you didn't have to explain it to people but I really do think it's an interesting fact about you, my friend, all of which is the longform of 'cool!'" and then smile winsomely and sincerely. Science refuses to cooperate with this wish, however, so it creeps up on me from time to time and that embarrassed, frustrated lockjaw fills my head again.
One time I was at work at the deli, standing near the opening of our little island in the store, doing something for some customer. The softly familiar scent of a particular perfume & toiletry combination drifted to me and a picture of the girl my best friend/assistant manager loved before all others resolved. Moments later, the young lady in question appeared at the counter.
My response? "I thought I smelled you!"
She looked horrified and then very angry, asking me to go get said friend. Friend told me later the girl now hated my guts and never wanted anything to do with me again.
I've always wanted to go back to that moment and tell her I was sorry she misunderstood, that I only meant she had a very particular combination of fine scents...and then I realised recently I'd really rather just be able to tell her to get over herself.
Someone once insulted a friend of mine as I was hanging outside the front of a fabric store and she was checking out, still inside. He was intensely rude and thoughtless, somehow believing anyone would want to hear his ignorant claptrap, not realising I was there with this friend. I wheeled on him and gave him an earful, producing a look of shock and anger on his face as he tried desperately to come up with some reason his hate was valid. He couldn't, so he sputtered then walked off.
My friend asked what had happened and I told her. She seemed happy I'd done this, even touched. I felt it was a normal thing to do but felt glad this had given her a good feeling.
Many times since then I wish I hadn't told her what he'd said and how I'd responded. I don't know precisely why, but it has seemed to me the better part of that moment was being anonymous in resisting ugliness, and going over it removed that layer.