Fiction has to be plausible. All history has to do is happen.
Many things are possible. Few things are certain.
You can write better about a place you've seen for yourself. You don't have to have been there - I've sure written about places I've never seen - but it does help.
A horsefly can't do a horse much real damage, but it can drive it wild anyhow.
I'm a social caterpillar. I am not a social butterfly
People you don't like are pigheaded. Your friends are stubborn, or hold to their purpose.