This was probably said, but people who drive 30mph in a 45mph zone during normal weather conditions.
Local TV news anchors who have only one job – correctly reading news off a teleprompter – and who absolutely cannot accomplish that task. I don’t mind if a friend or an acquaintance mangles a celebrity’s name, or mistakenly pronounces “nuclear” as “newk-you-ler” – but when someone is getting paid to read words aloud (and, presumably, to pronounce words correctly) – I hold them to a slightly higher standard. Maybe, get to the studio a bit earlier, and do a practice read-through, first? Maybe, have a reading coach on staff, to correct such errors? It seems like these sorts of things ought to be a priority on The News.
(By the way, I’m not talking about news anchors who make one or two mistakes in an entire career, but those who repeatedly make such mistakes.)
Accept that some words have more than one correct pronunciation. Also there are regional pronunciations.
My sister has terrible computer skills. And her boss was even worse. I had to teach her ctrl-c/-v, but at least she uses them now. But she got a chromebook when she retired and will use it when we’re watching TV, so I can see what she’s doing. She never opens multiple tabs in her brower. Like not even one additional one. She will close the window. Open a new browser window to go the new site. It made me wonder if that’s what she did at work! I’ve tried to show her how to open multiple tabs, but she gets crabby and tells me to leave her alone. O.k.!
Related to this are spelling errors in the banners (names and locations) and the “crawls” across the bottom of the screen. I have called the newsroom before to complain about spelling errors!
People who pronounce “legislators” “leg-is-la-TORS,” with the accent on the last syllable. This is a thing here in Mississippi. I’m guessing it might be some sort of hypercorrection by speakers who want to make their pronunciation of “legislator” and “legislature” really, really distinct, but it sounds super-artificial and weird.
How about contextual errors, like the crawl that proclaimed “Death-related deaths are up in 2024”. Really, now, you don’t say? (They meant heat-related deaths, this being Arizona.)
But for me, that doesn’t fit the OP. I thought it was hilarious, rather than infuriating.
You reminded me of this: years ago, the local news wanted to wish a Happy Passover… but because someone got the aspect ratio wrong, the monitor next to the news anchor read “appy assover.”
This was not infuriating to me–just hilarious! But I don’t know how other Jews felt.
As @Just_Asking_Questions mentioned, it may not fit the OP.
(For those unfamiliar with the holiday, Assover is when we celebrate people who move their “ass over” to make room for others to sit on public transportation.) 
That makes me very Appy.
We have a similarly strange thing here, but with the accent on the first syllable: for “insurance,” people don’t say “in-SHOR-ence,” but “IN-shor-ence” (as opposed to “OUTsurance”?)
Then 'at’s the ‘oliday for you, ol’ chap!
Yeah, that’s a thing here as well, but that one doesn’t bother me as much for whatever reason.
What would bother me is pronouncing the middle syllable as SHOR rather than SURE. 
I am well and truly tired of making the typos, “Tohte,” “Fromteh,” and “Onteh.” It breaks my rhythm when typing and it happens often enough to really piss me off.
I’m pretty sure I’ve posted about this before, but the bastardized spelling of ‘whoa’ to ‘woah’ always pisses me off.
Another YouTube annoyance…
When I see someone in a video holding a lapel mic between their fingertips in front of their face as they explain something as the gospel truth, I immediately apply negative points to my evaluation of their content, and I will probably move on right away.
For some reason that pose strikes me as an affectation, and it bothers me. But why? What’s wrong with a guy holding his lav mic in his hand instead of clipping it on his clothing as intended?
I was just going to mention that! 
I know someone who I kid because he does this all the time with words, as in “I’m gonna take my UM-brella as IN-sher-ince in case it rains on my way to the MYOO-zee-um”
It sounds weird when you put the em-FA-sis on the wrong si-LAB-el
“As my cart is blocking the exit, I’m legally still inside. So what better time to stop and check my receipt?”
I see you’ve met my late great auntie Shirley.