Mine is SiriusXM. When I feel like I want to con them out of trials with multiple accounts (because they don’t really keep account information for too long), I have to go to their website because their app is essentially useless unless you’re subscribed. But their website is awful because of not design alone but function. Their lookup tool for license plate, VIN or radio ID never works so it’s pointless to try. They don’t make it apparent that you can select the stream access, they make you have to waste time before you figure that out.
And their tech support? Awful.
Debian’s site is awful. I hate when there’s some giant, useless picture that you have to scroll an entire screen-length past, and then everything is still absurdly spaced apart. Look at those dumb, giant icons. Compare to debian’s site from 2018: https://web.archive.org/web/20180208023935/https://www.debian.org/ which is so much better. And actually contains information relevant to why you would go there in the first place.