With Samba, when I share inside my home folder, I only need to right click the folder I want to share (Let's assume it is on the Desktop) and select Sharing Options, then just select the options I want to share it as and that's it, the user, be it in Windows or Linux will be able to see, copy, paste and basically have the correct access that I selected for the share without too much hassle. This is specially true if I allow the guest option when sharing.
If Samba is not installed, it will prompt me to install it and configure it in 2 or 3 clicks when I try to share a folder. After login out and in, I can share any folder inside my Home and be done with it. The user from Windows or Ubuntu can see my PC and the sharing resources with no problems at all. There is no additional steps to configure permissions aside from the 2 or 3 Samba Share options when selecting the Sharing Options in the context menu.
The problems arise when I try to share something outside of my HOME. For example, a mountable unit. Doing it the same way I mentioned before does not work. The external user either can not access the shared resource or can not see it. I have checked to see the permissions and ownership of the mountable unit (They are exactly the same as my home folder), but still Samba does not share anything outside of HOME as easy as something inside of it.
What is the difference then, between sharing something inside and outside of HOME assuming both resources have the same owner and permissions.