A Real Best Friend wants to hear about your day, your pointless stories, your silly drama, etc.
If you’re going on about a co-worker pissing you off and the only feedback you get are “uh-huh’s??? and “mhmm’s??? and head-nodding, that’s not someone who has much interest in your life. Everyone knows your bestie is the person you call because they will get equally as angry as you are about the silliest little things. They should be the ones saying, “They said what to you?! I will fight them.”
A Real Best Friend hates your douche bag ex probably even more than you do.
I don’t even think I need to elaborate on this one. It’s pretty much just a given, and if someone doesn’t curse his name when it is brought up in conversation, they are not your best friend, my dear.