A recurring note a story artist may get in the production of an animated feature is to tone down the angry eyes. We all try to draw fast and loose but, in the middle of it all, nuance may escape us for a brief moment. Arched eyebrows and a furrowed brow usually tend to read “angry”, even if we’re trying to express focus or determination. I would even say that, overall, it’s easy to overdo an expression. I’m not saying a pushed expression isn’t exactly what’s needed at the right moment. I’m just saying that the audience literally looks for the character’s expression first when looking at a sketch or panel. Keep that in mind and lure you audience in with slightly more nuanced expressions, until the right extreme expression calls for it.