It’s a pattern of behavior. If a user spends their time nitpicking every minor detail of a comment, but seems to be incapable of understanding that other people have different ideas, or worse purposefully parses someone’s language incorrectly just to continue an argument back and forth without any progress or even a desire to see a resolution, only wanting to have the last word, I consider that to be trolling. Nobody has benefited from the interaction, and everybody leaves frustrated, annoyed, and only further entrenched in their original position.

I think people have pretty different ideas of what behavior counts as trolling, but simply disagreeing with a user or not liking their posts doesn’t make them a troll.