The obvious trolls on the internet and in real life typically are harmless to all but the most naive and quickly blow their own cover with their outrageous stories or pre-emptive money requests.
Those who walk the fine line between emotionally unbalanced attention seeking and bona fide posting are far more intricate and fascinating. They are, in essence, emotional con artists and wreak havoc in person so the internet is like a giant playground to them. Actually the fewer lies they tell, the more dangerous they are because their deceit is more difficult to unravel.
The skilled ones are masters at manipulation and will emotionally drain their willing, sometimes gullible, audience with their curious ever-changing blend of fact and fiction. They are interested primarily in stealing attention and sympathy, not money.
Of course, they are always handy with an often legitimate-sounding explanation when called out on their inconsistencies because frankly most of us sometimes forget minor details.
The drama queens (and kings) can intuitively sense when they need to tone it down so that their mark does not write them off as a sensationalist. Whoever it was that mentioned how these people use hyperbole to describe a minor annoyance as a horrid happening was spot on.
In my community, a person spun a story that paved the way for them to become a highly visible spokesperson/poster child for a certain cause, a coveted position for an empathy thief. Enough of the story was legitimate so that people did not bother to confirm details initially.