These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Foe Yay: Many fans ship Jane and Gunther in spite of their obvious hatred for one another. The creators of the show probably saw this coming and devoted an entire episode to the two dealing with rumors that they're in love. Naturally, this is probably the most popular episode.
Jerkass Woobie: Gunther. Though he often behaves unpleasantly and underhandedly toward the heroes of the show, one can see how his life is truly quite sad, and many viewers are sympathetic toward him; he is motherless, and in all likelihood a victim of child abuse by his Corrupt Corporate Executive father. He is also constantly torn between duties towards his amoral father and his duty to uphold the knight's code, perpetually between a rock and hard place from which he cannot escape, and Word of God says he desperately wants to be liked, but just can't figure out how.
Ship Tease: Several moments between Jane and Jester could be argued as this.
Tear Jerker: Dragon tries to get Jane to remember who he is and get over her fear of him, and almost doesn't succeed. The look on his face after she tells him she hates him is heartbreaking.
Smithy's speech in "A Pig of a Problem"—you can hear his voice cracking.
Pig is going. Forever. Or she will be, and I need her. Need her in my forge—work in company, I guess. She has never let me down, not once. Never too tired, you know? Always there and never asks me for anything. And now how can I help her—how can I? Right when she needs me!