Strangers who smile at you, sincerely
summer days that are not hot or cluttered with work
rich food that does not make you regret it later
hearing a song on the radio you used to own, years ago
remembering to deliver a message from one friend to another, a week later
a news story that matters to you, with information you had not heard before
a camera angle in a film you have never seen, or an actor playing against type, in a way that surprises you

It is the rareness of these that makes them special, so though seldom seen, they are seldom forgotten