It's wrong to call people's work boring.
Terry is in an art class and sees an art piece made by a classmate.
Terry wants to comment on the art piece.
Terry gives constructive criticism to his classmate on the art piece.
Terry calls the art piece made by his classmate boring and keeps making fun of it.
Terry's classmate thanks Terry for the constructive criticism and improves his art piece.
Terry's classmate starts viewing Terry as an unfriendly and rude person.