1) Someone who hurt us on the assumption “I can hurt him/her, they’ll forgive me anyhow”.
2) Someone who was motzie shem rah on us.
Here it seems you did it without any malicious intent. In fact you meant good. We still have to do all we can to undo the harm.
If we do all we can to undo the harm and seek forgiveness (if it wont make things worse), things can work out. Someone showed me an article, I think from the yated, a couple of months ago, about a person who was insensitive to a collector on the way to her daughters wedding.. After her daughter was unfortunately suffering with fertility, s/t prompted her to think how she may have hurt anyone.. She thought and thought until she fell asleep. Eventually she remembered the story.
She resolved to ask forgiveness, but had no clue how to find her. Went to hall after hall every night to look at the collectors, no where to be seen. Out of no-where she spotted her in the airport when she (uncharacteristically) took her daughter there on way for treatment.
Asked forgiveness, got the news that— her daughter was expectant..!