Twit or twat

I don't mind swearing. Others do, but not me.
For me it provides another form of expression, something a bit edgy, something that allows a release. It's just a word or words, nobody gets physically injured and you either take offence or you don't.
Anyway, we were in the car the other day and the driver in front did something dangerous.
"What a twit," said Jan.
"Whoa," said I, "he's not a twit, he's a twat."
Jan looked at me with disbelief, so I had to explain the difference.
"A twit is someone who is harmless and does silly things that basically don't offend anybody. A twat is altogether a more unpleasant character."
I love language and we English have so many words, many more than any other language, to express ourselves.
The thing I dislike more than swearing is inventing stupid words. Take the word poo. It has come into common usage as a more genteel way of saying excrement or faeces or crap or shit (but then you knew that). We've already got lots of words for it so why invent another? And, to me, it isn't more genteel or acceptable because it means exactly the same thing. It's a word that you usually associate with talking to a young child.
That's another thing I dislike, talking to young children as if they're imbeciles. Someone we know when talking to their young children says 'juicy' instead of 'juice'. Hmmmm.
These kids are now quite capable of understanding the world as it should be spoke. Geddit?