My current pet peeve is W10/Microsoft Edge.
When I first got my current laptop, I set up Google Chrome as an alternative browser, & checking regularly over time, it had remained functional.
SWMBO & I are old codgers, she is semi-disabled, so we have taken to buying a weeks worth of pre-prepared meals from a company called "Lite 'n Easy".
After initially battling their disorganised website, we used to order on line with no problems, until we discovered that thanks to the Federal govt, because of her condition, Steffi was eligible for a discount on their products.
This only applied to her, & I had to keep paying the full amount for mine.
Steffi was duly issued with a special number after her name on our account, being assured all would be well.
It wasn't-----The company kept charging us the "full whack", & after umpteen attempts on line, we reverted to ordering by phone.
After a while, this became tiresome, so we would try online every now & then.
Eventually, either they fixed a problem at that end or one of the W10 updates did it, but we could now order on line, with the charging working properly.
Duly "chuffed" we settled in to the new routine, until, suddenly, Lite 'n Easy refused to recognise my password.
Having tried everything else, I tried "forgotten your password" & they sent me a temporary one.
Rang them, talked to the lady who said that "Yes, that happens sometimes, & the best way around it is to use a different browser!"
"Magic!", thought I, "I'll just go on Chrome!".
Clicking on the icon, nothing happened!
I finished the phone call, then spent most of the day Googling for a reason why suddenly, Chrome wouldn't work with W10, all to no avail.
I even uninstalled the old version of Chrome & tried to download a new one, but W10/Edge didn't let me.
Eventually, I did what I should have done at the start, tried accessing the website with my mobile phone.
That worked perfectly, & I put in an order, but I hate using a phone for such things.
After we finished our evening meal, I had another look at the laptop & downloaded Firefox with no problems.
That browser worked perfectly with Lite 'n Easy's website, too.
All is "sort of" well, but I now have to change browsers to use a website, when I was formerly reasonably happy with Edge.