[hamilyon2]

Even if your ip address/domain is not in the blacklist right now, it only takes a few people marking your correspondence as spam for it to be blacklisted. Since everyone is on these big free providers, nobody will ever see a single email from you any more. With less centrally controlled email, that would not be possible. I think that is the problem everyone is talking about.

[grishka]

People generally know to check their spam folder if they're waiting for an email but it doesn't arrive.

[kiwijamo]

I generally don't check my personal spam folder. I've honestly not seen any false positives with Fastmail. But I certainly do have to check every now and then for my work O365 account which is pretty bad at marking legitimate mail as spam. YMMV of course.