If 10 is average my stats are way too low.

10 is average for an adventuring hero. Not necessarily for most "civilians" if you want to call them that.

Eh, a ten will give you about a 50/50 roll if something is "easy," and only about a 25% chance if something is "medium" difficulty. Sounds about right for me. Am I gonna shut my damn mouth when I should? 75% of the time, no.

Incorrect. Commoner is all 10s 

Hey baby

Intelligence is knowing tomatoes are a fruit Wisdom is knowing never to add it to a fruit salad

"Charisma is a sex appeal" is funny, but that's not really entirely accurate. It's about motivating others towards your goals whatever that may be, having a presence that commands attention and being a good communicator. That's why charisma helps disparate skills like lying, persuading, intimidating, and performing. Sex appeal may superficially help some of those things, but so does a half-giant that makes you piss yourself with their mere presence, or an old fat guy who speaks with clarity of conviction and intelligence. Ain't nobody want to fuck Winston Churchill, and he was an asshole as well. But he was a very charismatic figure, still.

Constitution is when you have to eat the fruit salad and there's tomatoes in it.

But the little cherry tomatoes rock in fruit salad!

What about fruit salad in a tomato?

Charisma is being able to sell a tomato-based fruit salad. That's how we got salsa.

I was more a 00's kid into consoles, so this was introduced to me via Fallout 3, then Dark Souls

Charisma is framing salsa as a tomato-based fruit salad

Dex is clearly green though

Int is knowing what you're talking about Wis is knowing when to talk Cha is when people listen to you

5e commoners are 10 across the board.

My Constitution is 0.

How charisma works: just say "hey baby". you're all welcome

Charisma is essentially Social Skills. Social Skills definitely help you get laid, but also convince a shopkeeper to give you a discount, persuade a guard to look the other way, etc.