Me too! You're in for a lot of pain, especially in the beginning, when trying to host your own mail server. Big players just dropping mails (Microsoft), local authorities refusing your mails (even on the postmaster inbox) and if your mail goes through it might still go straight to the spam folder. Granted, I'm using an .xyz domain, but I'm not sure how big of a role this really plays. Interestingly I didn't have problems with Google's mail servers so far.