Worf was sometimes the biggest emo on TNG.
Well "emo" might be too strong a word, but when I saw the title of this thread my thoughts were along those lines. The first image that springs to mind is from that episode where the crew's fears are all being drawn out by some force and Worf hastily flees the bridge, recites some Klingon words in his quarters, then proceeds to nearly stab himself to death before Troi stops him just in the nick of time. He explains that he's ashamed of himself and feels he isn't a warrior anymore because he feels fear or something. It was somehow kind of touching and also hilarious at the same time. I can't remember the name of the episode of the top of my head, but I'm sure someone else can.