Edit: Fragile. Argue this all you want, but I will never change this opinion. I'm sure INFPs can kick ass and take names, and have a lot of confidence.. But they are easy to break, by nature. SOME may defy this, and may be much more resilient than others, but.. Yeah, fragile.
I know a few INFPs - mostly male, which I think is odd.
One is incredibly sensitive, and will NOT shut up about is girlfriend, who broke up with him over a year ago. He annoys the piss out of me, and is whiny beyond belief. I told him to move on, and he told me I am mean. Ha.
I know another INFP, who is in his late 20's. Also very sensitive, but not whiny. Very artistic, and definitely has his head in the clouds. Enjoyable to be around. He's very nice.