Pictures, experiences, paragraphs of text, videos (especially videos) wanted: How do you tell a Fi-valuer apart from a Fe-valuer? How do they behave? How do they form friends? How do they speak?

I'm told that seeing whether someone is Merry or Serious is one of the easier ways to narrow down someone's type. So. How do you tell?

EDIT: And no Fe versus Fi arguments. Make a different thread for that.