I hate when new version of program removes one feature that I use, no matter how insignificant it may seem. Once you get used to something, it is always hard to let it go.
When you go to "Safely remove" your USB disk in Windows XP this will also close any Explorer window that has drive listed.
Then Windows Vista came. In Windows Vista you will get an error if any program is currently accessing drive that is being removed. This includes also simple viewing of content. I can understand reasoning - this was "proper" way to do things - no special behavior for any program.
It came to me as a surprise that Windows 7 brought "old" behavior back. It just feels much more humane when computer does obvious things for you. And it definitely shows problem with Windows Vista - lot of small annoying things.