These days (everything forwards to gmail) ...
So you've gone with a deliberately unreliable mail system which BY DESIGN will automatically THROW AWAY SOME OF YOUR EMAIL with no notification either to you or to the person who sent it. Do you know how many emails you have NOT received that weren't spam ? In addition, they've enforced some systems (eg SMS) which were known to be broken before implementation, and were known to break a lot of legitimate email usage before implementation. But hey, this is Google, big enough to say "screw you" to the rest of the internet - we're changing stuff and you'll change to suit what we impose" to those who actually do run reliable mail servers.
My own mail server is set up to NEVER discard an email - it does NOT accept mail before it's done all the spam checks etc, and if the mail fails then it rejects it which means that any false positives result in the sender being notified. Once you have accepted an email (as Gmail, Microsoft/Hotmail, and all the other large providers do) then you have limited options - you can't notify the sender or you become part of the problem (backscatter), and notifying the recipient rather defeats the point of blocking spam - and your only option is to SILENTLY THROW AWAY any email that fails your checks whether it is spam or "ham".
Would you accept it if your postman went through your snail mail and threw away anything that looked like it is junk mail ?