1. Some one who does not comment on your post with words such as incredible, you are awesome, great post.
2. Some one who disagrees with your post.
3. Some one who disagrees with your post vehemently but stays away from any personal attack
4. Commentator who disagrees with you in a personal post on a personal decision.
5. Some one who calls you name because they disagree
Now, who will call you a troll based on the above definitions? 1/2/3/4/5
In real situations, do you still maintain that.