What do you guys think are the main differences between an INFJ and an ISFJ? I'm definitely an INFJ, but I know a lot of people who are ISFJs that *think* they're INFJs and probably aren't. Helpful Sponsor Ads! My experiences with ISFJs are they are very focused on the past. They can also hold grudges like you wouldn't believe. Because ISFJs use their past experiences to 'figure out' people, if they've been hurt in the past, they come off as very paranoid. Or falsely attribute negative intentions to you. Other thoughts?