Warning: Subliminal programming in the wild
It is quite likely that lots of content on media (video) hosting sites (mainstream and especially "alternative") has been augmented (or poisoned) with a range of subliminal (and supraliminal) programming techniques, that are far outside of the (unofficially) accepted norms. This is highly unethical and dangerous, but hard to forensically prove. As best practice stay alert, stay relaxed and stay offline more often.