Sooooo many things in UK culture passed off as "normal" and definitely mentioned: tattoos and fillers. Not "anti" either but it is so common.
Maybe already mentioned:
People buying from Shein and Temu because it is a bargain (but ignore the human cost of forced labour and child labour.
To ignore the damage to our planet of all that (Shein/Temu) crap produced (and breaks and discarded), shipped globally and is, in many cases, hazardous (chemicals).
Borrowing at least 1/4 of a MILLION pounds for a very small home most places in the UK
Putting your bin out for collection without thinking where the hell are they going to put all this non recyclable rubbish
Using steroids on animals, eg chickens, to increase growth rate and eat that animal
To typically spend 37 hours a week in work
To be expected to sit all day in an office job
To be expected to use online banking/shopping/everything and, despite cyber attacks, we are increasingly coralled by "authorities"
Fake teeth, boobs/cosmetic surgery, lashes, brows, tan hair extensions, piercings (I have pierced ears but it is a weird normal), lips, liposuction, gastroband etc People who have had the work on their face look like Jim Carey in The Mask (but not green-skinned)
To smoke/vape/alcohol
I am not saying people shouldn't make their own choices but all the above (and loads more but I am boring myself now 😂) are perceived as "normal" but are unnatural = weird