Debbie Downers are miserable people who seek to make others miserable
It's just a fact of life, it is what it is
The internet gives these people a life and a purpose and a vouce they don't otherwise have in the real world
There are people who behave in the same manner in every thread, those are the biggest issues. People who bring nothing into every thread they enter.
Then there are people who fight with everyone everyday
Or people who fight with each other all day long, day after day, week after week, month after month, year after year..
All of them some indication of the lack of social skills