Yesterday

INFPs are flexible and laid-back, until one of their values is violated. In the face of their value system being threatened, INFPs can become aggressive defenders, fighting passionately for their cause. When an INFP has adopted a project or job which they're interested in, it usually becomes a "cause" for them. Although they are not detail-oriented individuals, they will cover every possible detail with determination and vigor when working for their "cause."

http://www.personalitypage.com/INFP.html