Today was the 10th of Tevet. It is a public fast day which is widely observed, although many
otherwise observant Jews do not fast, seeing that it is one of the "minor" fast days. Halakha allows people who feel unwell, the elderly etc. to eat.
So, here's the story. Today I was walking through one of Jerusalem's shopping malls. I saw a man who I know as a "kippa wearer" walking in front of me. He was bare-headed. My thought was: "Interesting! ... Maybe he doesn't cover his head all the time; maybe just in a Torah class, or when eating. OK! No problem."
Then I noticed that he was drinking water: "OK!" I thought to myself. "He is an older man. Possibly he has medical reasons to drink. Maybe he was never raised fasting and he doesn't fast on 10 Tevet."
But 2 minutes later, he put the bottle down, and re-fastened his kippa. Suddenly I understood. He does wear a kippa. But he didn't want to be seen drinking water in public while wearing a kippa, so he took it off to drink on a fast-day.
And I thought how amazing his sensitivity was, to the meaning of wearing a kippa, to the sanctity of the day, and I just thought עם ישראל קדושים הם - We are a holy nation!
In Judaism, we are taught to דן כל אדם לכף זכות - To judge every human in a generous way (Avot 1:6). It is a practice that I try to apply (I'm not always successful), assuming that most people are not ill-intended, or deliberately nasty. This was a great reminder how we should never judge a book by its cover, but instead always assume that people have the best intentions in mind.