Is it possible to exclude certain email addresses from being emailed?

Yes, there is. You can add a comma-separated list of emails or patterns.

If, for some reason, you want to temporarily exclude certain email addresses from receiving emails, you can add them to this exclusion list and then later on remove them. 

For example, let's say that a customer emailed you after receiving the abandoned cart email #1. You want to prevent them from receiving the abandoned cart email #2 a day later, but you don't want them unsubscribed from all emails, you could add them to the exclusion list and then remove them a day later.