Great idea for a thread, OP - thanks!
1, Abusive (as in 'of your assumed goodwill' rather than threatening or aggressive) bacn - I think it's actually worse than spam, tbh. With the latter, you all know where you stand: that they're very happy to lie or scam you in order to hassle and trick you out of your money; but when they're pretending to be your friend and making out like you actually want to hear their relentless daily marketing tripe, just because you once/occasionally buy/bought from them, it's actually a lot more annoying.
One of the most irritating facets of this has to be the companies that send emails before Mothers' Day, Fathers' Day, St Valentine's Day etc., asking if you want to 'opt out' of their marketing emails (that you never explicitly asked for in the first place) - 'because they care and don't want to upset anybody'!
Complete load of cobblers; and by expecting you to engage - and being asked to click on a button that may well serve as a painful reminder, in order to stop the marketing, IS very much expecting you to engage - they should just own the facts: some people will be glad that they've contacted them and reminded them, and will follow up with purchases; many, probably most, won't really care at all and will ignore it; but a significant proportion will be very upset at the reminders that you've deliberately sent out, in full knowledge of that fact, on account of the fact that your only actual concern is in getting people's money.
2, I almost agree with a PP about cookie notices, but I don't actually mind the 'fair' ones that allow you to click on two or three buttons and reject/object to all. On the other hand, the real menaces are the ones that force you to spend 10-15 minutes manually turning them all off. Until relatively recently, there was actually a popular online parenting forum that did exactly this.
They so clearly hope that you will not bother starting to turn all the long list of cookies off, or that you'll give up and reluctantly allow them your default 'non-consent'. Or even that you will have the patience to turn off every cookie, but then will accidentally negate it by clicking on the huge pretty, brightly-coloured 'accept all' button at the end instead of the tiny grey 'save my choices' button.
And as for 'legitimate interest', that concept is one of the biggest scams going ever - when you have to click on a second screen behind and turn off a load more, assuming that you actually realise that 'reject ALL cookies' means 'oh, but not all these other ones of course'.
Unless it's an amazing site and/or I can't find another one that will let me do what I want to, I just back straight out and leave their site immediately; killing the golden goose and all that.
3, Unskippable ads in YouTube videos. I understand that it's an extremely expensive site to run, and that the owners want to make money. I don't mind the ads where you can watch them if you're potentially interested and then, if not, skip after 5 or 10 seconds.
However, I hate the ones that last a minute or considerably longer. Especially when I'm wanting to hear an old rock 'n' roll song from the 50s that is shorter than the pesky ad! When I know for a fact that I categorically, assuredly, unquestionably do not want to sign up to Grammarly, it's not actually helping either of us to delay every single video that I click on for a minute or more with that exact same ad over and over again.