Why does Gmail start marking emails as spam after a certain point?

Question

gmail

I noticed a very unpleasant behavior of Gmail'a. Subscribed to several mailing lists, and if I delete messages as unread or open and delete them almost immediately, then Gmail starts to consider them spam after a while. This situation annoys me very much, because if 10 letters come across one necessary one, and for some reason I don’t want to unsubscribe, then I regularly have to comb through spam, catching what the gmail put there. Moreover, according to my observations, if there were no mailings for a long time, then my actions are not even needed - the letters themselves go to spam! For example, some online game sends a letter once a quarter, and I eventually find it in spam. In none of the cases did I click the "Report spam" button myself. I also don't use any desktop client, only the web version.
I'm not even complaining that the IBRD plastic card report automatically ended up in spam, it was an accidental discovery for me to find my financial data among penis enlargers and prostitutes. :)
Has anyone encountered a similar problem? How to solve it?

Answer 1

You can solve it like this:
settings -> filters -> create a new filter
In the "from" field - insert the box where the mailing is coming from, -> next -> Never send to spam -> create a filter

Answer 2

All my mailings are sent to the "Mass mailing" folder.
This is after enabling the experimental Smart Shortcuts feature in Gmail Lab.
True, I did not try to delete unread.

Answer 3

Faced - debug letters and reports from servers fly to spam. Once I pressed the “Not Spam” button, they normally enter the inbox, as expected.