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@morsCatan By aggressive, I meant aggressive in comments - swearing, abusive etc
People who play strategically I have no problem with.
The cruel players I referenced are a very few who do not play strategically, but cruelly. I saw one person deliberately hem in another player, to no obvious advantage (they didn't build there, and weren't trying to race to key resource tiles), and then proceed to steal off that player (who now couldn't go anywhere, and was stuck on 3 points while I was leading on 6) until the persecuted one quit. Maybe there was a backstory there, but if so it wasn't stated. It just seemed to be about messing with someone's head. I have only come across two players that have played cruelly, and really never want to play with them again.
Clever strategy - no problem. I still remember one player who gave me a stone in trade for a wood, and then played a monopoly card for all stone. Boy did that hurt , but it was clever - so I laughed and typed 'Kudos Machiavelli' in the chat.