I really hate it when websites override Safari's scrollbar and substitute a 5px one that may fit the theme of the site, but is virtually impossible to grab because its hotspot is only a tiny bit larger than the edge of the window.
Nowadays, I find the only interaction I have with the scroll bar is to look at it to determine how far down a page I am. I always use the scroll wheel on Windows or the two finger scroll on the Mac trackpad to scroll a page.