If you want to create any normal listing based on category or content type and say have it appear in a block across several pages, but want to make sure that the page you are currently on doesn't appear in the list, then the below should help
Instructions made from a collection of information found in Drupal website...

1). Open up your view
2). Create an argument of Node > Node id.
3). Then choose the radio button option of "Provide default argument"
4). Some "Provide default argument" options should appear. Under "Default Argument Type," choose the radio button option for "Node ID from URL"
5). A little lower you should see "Validator options." Where it says "Action to take if argument does not validate," Select "Display all values"
6). Just below that, checkmark Exclude the argument
"If selected, the numbers entered in the argument will be excluded rather than limiting the view."

Save and test!