Why does someone look back to stare at you and doesn't break eye contact at all then tries to go near you or sit next to you?

Have you ever reflected on why certain people, despite showing signs of trouble, don't receive the help they need early on? What could be done differently?
Why do some people manipulate you into being 'provoked,' or 'getting a reaction out of you,' just to twist words and say you 'are the one arguing with them'? My step dad does this frequently.