Nobody likes a toll.
People do their best to ignore them but it can be pretty hard.
You can block needless and vindictive accounts, and flag offensive comments, but their persistence is relentless.
A new study has suggested the reason trolls behave as such may be psychological.
A study published by Science Direct explored the personality traits of online trolls, examining their levels of psychopathy, sadism and empathy.
415 people (36 per cent men, 63 per cent women, 1 per cent other), with a mean age of 23.37 years took part in the research.
Results showed that men were more likely to troll than women, while also possessing high levels of psychopathy and sadism.
Unsurprisingly, trolls had lower levels of empathy and their psychological traits tended to lean more towards the nature of trolling instead of, say, compassion.
The study also discovered that trolls could strategically predict the emotional suffering of their victims.
Therefore trolls are not only manipulators of online discourse - they can easily manipulate other's emotions.
Scary, but interesting.