Personalized vs. Shared View of a Page

One of things my users have asked about and/or have been confused about is why some web part menus say "Modify SHARED Web Part" and others say "Modify MY Web Part." I've done a little reading and have discovered that there is both a "personalized" and a "shared" view of a page, and that seems to be the determining factor in what the web part menu says.

My question is: Can someone provide a good explanation (or link(s) to a good explanation) of how this works so I can do a better job explaining it to users?

If you're an admin you have the ability to modify shared views that is the standard view that is seen by all users, but admins can also create personal views that only apply to them.  Similarly non-admin users can create personal views as well. That's the difference.

Thanks. That makes sense.