Your Spam Filter is absolutely horrifying
Your spam filtering algorithm is getting progressively worse and worse. It seems as if every time I delete an email within some brief time period, or even if I just delete an email at all, the sender will get sent to spam next time. Today I saw in my spam folder three emails from email addresses that I have either interacted with or whose emails I have saved. I saw in my spam folder two emails from a friend of 10+ years whose same email address I have been emailing since I first got this email account. I have emailed her hundreds of times. I have emailed her within the last month or so! And her messages were sent to spam. That is INSANELY terrible spam filtering; your developers should be ashamed of this awful, lazy attempt at an algorithm. I could write a better spam filter than this. Dear God, you guys. As this gets worse, the time cost of making GMail my main email account is seeming less and less of an issue. If you guys are struggling to retain customers and make money, look at yourselves. The only ones to blame are you.

Sorry to hear you are unhappy with our spam filters. Please reference this article regarding filters: https://help.yahoo.com/kb/manage-spam-mailing-lists-yahoo-mail-sln28056.html.