Why do most people get offended when a stranger simply says one thing nice to u

For example, an employee is cleaning carts for everyone and lets each customer know they’re all sanitized. So he told this lady and she just gives him silence for like 5 seconds while getting her cart and you can tell she looks annoyed and all she says is ok.

My mom and I are at the park and she sees someone daughter wearing a mask who’s the same age as my son and he can’t wear a mask (all too small and always takes it off) so my mom tells the mom in Spanish assuming she’s Mexican, that’s so good your daughter is wearing a mask and the lady all she says is “aren’t they suppose to” rudely. My mom likes talking to strangers specifically old people that’s just how she is.

Like is it wrong to spread love around the world and just not get offended by everything. I wish for a world where strangers can just simply have a nice conversation or give a comment without looking at then other person like their weird.