Note: this is a "vintage" tip for older computers/systems.
If Address Book "hangs" (spinning "beach ball") when trying to create a new smart list, etc the address book database might be corrupted. Try exporting the entries, then quitting Address Book, deleting the Address Book folder in the user library, in the Application Support folder. Run Address Book again and import the entries.
If the entries won't export they are probably lost because the database will need to be deleted anyway!