My niece's husband is a black cab driver in London.
I asked his opinion on your post and he showed me the laminated sign that he has on the glass partition separating the passenger compartment from the driver's compartment, it read:
If you have a preferred route, please inform the driver.
I asked him why it was there and he said that some passengers have an idiosyncrasy about routes, they'll get upset if you run into traffic, and ask why did I not take so and so route.
This way, if they opt for a certain route, even though he KNOWS there is a quicker and cheaper option, and tells the passenger this, it is down to the passenger, for the customer is always right.
e.g. there are two obvious routes from Trafalgar Square to Cannon Street, one is straight down Strand, along Fleet Street to Ludgate Hill, then past St.Paul's. into. Cannon Street, mega traffic and traffic lights all the way.
The other is Northumberland Avenue, left onto Victoria Embankment, left at Puddle Dock, right into Queen Victoria Street then into Cannon Street, marginally longer, but no traffic, and probably ten minutes quicker, virtually the same metered fare.
He said he'd use the Embankment all day long, but some passengers feel that they're being mugged into a longer route and say, "Not this way, can we go via Fleet Street?"
On occasion that may be £1.80 to £2.20 more.

One that causes flames to seep from my ears is when my wife is driving and we come to an inoperative bus lane, but she won't go in it.
I WANT to say, "Light of my life, the bus lane is posted as 07.00 - 10.30, Monday to Friday,
right now it is 11.15, and today is Saturday", but fractured eardrums from the past remind me to bite my tongue and resume reading the paper.
Absent a gun to my head, I adamantly refuse to drive as we live in central London, so I guess I'll just have to bite the bullet.

Clients making impromptu visits to the office during my lunch break.

When people pronounce Junko as junk-oh, Kato as kat-oh, Yumi as yum-me, Ichiro as eye-chee-roe, Jiro as gee-row and Yoko as yo-ko. All wrong.

(Can you tell I've just suffered an American Youtube review of a Japanese film? )

People who use the fact that a queue of traffic has slowed down and moved to the left to allow an amulance through as an opportunity to overtake.

Sitting on the bus in front of someone who had horrendous bad breath. The fumes were like an unflushed toilet filled with fag ends.

Low-hanging branches.

Gravel.

Those paving stones with the bumps and lumps designed for blind people. Evidently, they weren't also designed with canvass shoe wearers in mind.

I remember pulling over to allow oncoming to pass down a narrow road and a million cars overtook me from behind causing a stand-off between them and the oncoming traffic. That really annoyed me. I had to wait ages >: (

And spelling and sentence construction, it's a informal forum, folk type hurriedly, it's not an English exam or job application. Posters always resort to this when losing an argument

But there's no excuse for would/should/could of - that's just idiocy.

Nit-picky clients. Urgh.

People who ask me a question just as I have taken a bite or started to eat something

Especially if the question's "Are you eating that?"

I hate being asked questions when the answer is obvious: "Are you sitting there?"
No I'm a figment of your imagination.

"Good book?" No I only ever read bad books! Bore off!

Or just someone typing quickly during a heated debate?

When just about to tuck into a meal, another person who has already just started pipes up "Hmm. Not very nice is it?"

I agree.
Especially with low hanging branches, the people who live in the posho area by me have huge houses and gorgeous gardens, yet they let their bushes/trees overhang onto the pavement. Branches strewn everywhere, and hanging out/scraping you when you walk past.

It is the correct terminology, because when on a train you may not stop at the next station on the line, and the next time the train stops isn't necessarily at a station (could be a signal).

Unwanted spoken voice interruptions on the Vital Football website.

Work have blocked access to running/fitness websites (trackers etc) but I can still go on DS

someone taking "my" locker at the gym

there are no assigned lockers, its just mine - ok...

People using phrases like "catch 22" or "false economy" when they clearly don't understand the meaning of the terms.

This smiley: It's so hand-wringing, "won't somebody think of the children", "poor me", "what is society coming to", etc., etc.

The terms "She Who Must Be Obeyed" and similar. Ahahaha, no really, hilarious. For about five seconds, in the 1970s.

Linkbait, especially ones like "How this stay-at-home mum made $2000 per month!" or "New fat burning pill takes UK by storm" that link to pyramid scheme or diet pill spam disguised as 'real' news.

Oh, and people using'comedy' names for websites, e.g. "fleabay", "twatter", "failbook", "wonkypedia", etc. Bad enough in written form (I once had a client who always referred to "Micro$oft", wow, subversive!), but worse is when they use them in speech, invariably following the use of said hilarious nickname with a pause and a smirk while they wait for acknowledgement of their comedy genius.

Or similarly, calling The Daily Mail 'The Daily Fail' or saying 'The Scum' instead of The Sun

....................that’s just about covered everyone on DS;........including me.

Not me, but I will admit a liking for 'twatter'. It does seem so apt.

And instead of 'She who must be obeyed', I prefer 'I will ask the Ubergruppenfuhrer at home'. It was said to me by a friend many years ago and it still makes me smile.