I'm to blame for the stiffness, since when TLing Stella I tend to lean towards literal accuracy that may hurt smooth flow of conversation. It's a tricky thing to translate because it rains terms on you and because really, really little things matter in describing the state and change of relationships between all of the various characters, which is what Stella is mostly about.
Though it's true that it's not much of a comedy - it's at its best when it's not trying to forcefully shove a gag into the 4th frame as yonkomas are expected to do.