When Normal aggressiveness is selected, maifloss will floss for invalid, illegit, bounced, nonexistent, available, banned, deactivated, inbox_full, and disposable email addresses.
This is a sensible option and the one we usually recommend for most users.
Remember that there's a "help me decide" link beside the Aggressiveness options that you can click on to help you decide which mode option is the best for your contacts list.
Related: