Why is the scroll bar in Windows 11 so narrow? In what world is this an improvement?

What a silly comment. You could scroll using just the mouse wheel with the cursor anywhere on the screen in MANY previous versions of Windows, including Windows 10. I know this because I just had Windows 10 yesterday. Today, sadly, I have Windows 11. Sometimes you need to go deep into a web page, pdf, or document faster than scrolling endlessly, and in those instances, the scroll bar is a necessity.

I've edited the registry to increase scrollbar width and height, but it's still not back to 'normal'; the 'borders' around the scrollbar are too wide, leaving the normal scrollbar swimming in a much too wide vertical frame. Microsoft, I insist that you make your poor new scrollbar implementation optional with a Setting.

Yet another example of Microsoft thinking they know what's best for their users and making changes when no changes needed to be made. Sad.

Yep, scrolling with the wheel through a pdf hundreds of pages long is not much of an option.

I don't know about the major issues of Windows 11 that irritate some people. I'm still encountering smallish changes (like the narrow scroll bar and the broken right click menu) that are annoying, esp. since the changes weren't necessary and don't make anything better.

That works fine for a small scroll amount (a few paragraphs) but is unwieldy for scrolling a large document or long web page. Agree w/ the original poster on this, a cosmetic change that lessens functionality.