Recently I needed to retrieve a zip file of some old work attached to my copy of an email that I sent to someone in 2011, using Gmail. It wouldn't let me, because the attachment contained "a potentially dangerous file". It informed me that "If you're sure the file is safe, you can ask the sender to upload the file to Google Drive." So somehow I'm supposed to send a message back in time to myself and tell him to upload the file to a service which didn't even exist yet? Absolutely ridiculous.