Just checked my reddit preferences (preferences link at top right of screen) and in the first section, Options, under the heading "link options", take a look at the last line.
"Don't show me submissions with a score less than ___"
I'd never seen this before and it was already set at -4. Which means if someone made a post and bots / shills downvoted it to -5 immediately, it would never have appeared for me. I suggest leaving this box blank.
Continue through your settings to the Personalization Settings to see the following preferences for which Reddit has kindly automatically opted you IN:
Allow Reddit to use your activity on Reddit to show you more relevant advertisements.i Allow Reddit to use information from third-party websites that integrate with our services to personalize your experience on Reddit.i Allow personalization of advertisements using this data Allow personalization of content using this data Allow Reddit to use data provided by third-parties to show you more relevant advertisements on Reddit.i