I've had Fe types tell me I "seem angry" before... it's not restricted to Fi/Fe.
They're usually wrong - it's often in text, and I sometimes feign anger for humourous effect. It really doesn't bother me when people read me wrong - I find it amusing most of the time. IRL, most often people describe me as being very calm - they're usually wrong too, although that's certainly the image I project. If I am genuinely angry/sad/feeling any powerful emotion I always deal with it by withdrawing. I can't deal with strong feelings in any other way. External input just confuses me.
I'm wondering if this is a key difference: do Extraverted Feelers have to publically emote in order to understand/experience what they are feeling? (Much like Extraverted Thinkers say they have to talk in order to know what they think or Ne-doms need to brainstorm...?) Is this why it's so important that your listeners mirror back what you are feeling "accurately"?