Google recently filtered some emails into spam for us. Those emails were sent by Google Docs, in response to us adding comments to our own private doc. This was

Google recently filtered some emails into spam for us. Those emails were sent by Google Docs, in response to us adding comments to our own private doc. This was all within the same organization. I've also repeatedly seen them suddenly spam filter individual messages in long threads of conversation. Like they weren't taking into account that a message was part of a two way conversation at all, even though they have In-Reply-To and Reference headers linking them to those non spam filtered conversations. They also randomly spam filter transactional emails that we send from our servers that are from our own domain, to the same domain as hosted by GMail, that is fully validated by SPF, DKIM and DMARC. That should never happen. We clearly trust our own domain, so if mail from that domain is authenticated, let the bloody email through 100% of the time! It's like they spent all their time working on how to blacklist email, and zero time working on when to whitelist it. The most important part of a spam filter is the whitelisting.