I've learned that you can't tell if someone is short-sighted by looking if they wear glasses. I've learned that most bad things are done through thoughtlessness. I've learned to apologise when I'm wrong. I've learned that you can't lose if you defend what you value most. I've learned that the trick with ice cubes when you're making mayonnaise and it curdles doesn't really work very well. Also relevant to recent events (except possibly that last one).