I know language is an ever-evolving thing but a lot of "new" uses I find really annoying:
FAIL used to be just a verb. Now it's a noun too - what happened to failure?
REFERENCE used to be just a noun. Now it's a verb and we "reference" things. What happened to "refer"? (Ditto TRIAL and TRY)
MILITARY used to be just an adjective - when did it become a noun? What's wrong with saying Armed Forces?
WELL used to be an adverb among other things, but it was never an adjective - how did that happen?
And many more.
Regional differences I always notice:
In Scotland we say "I was sitting". Some English dialects say "I was sat". I know the correct form is "I was seated" but it sounds too formal for everyday use.
In England something needs doing. In Scotland it needs done. That due to a different linguist heritage though. Just as "gotten" is acceptable to us but seems to annoy so many English folks.
Also we say "You had better..." but I've heard some English people say "You better had". I don't know how widespread that is though.
I'm trying not to let the current teen habit of "I'ma go to bed" get to me, but it's not easy.