Re: I didn't bother with a third party anti-virus for Win10
-applications and features being suddenly disabled or removed without your permission,
-demands for money to use your common applications e.g. card games,
-advertising all over the place for services that people want to push you towards,
-leaking of your personal data,
-browser hijacking where your favourite browser gets periodically replaced with one under the miscreants' control,
-unexpected reboots and changes to your environment.
Hang on, that's just Windows 10. When are you getting to the effects of a virus infection?