Sounds like a classic subtlety case – you want the jaw to shift just enough so the cheekbone pops, but not so much that the lips go wild. First, name your curves like “Lip_Smile_Left”, “Lip_Smile_Right”, “Jaw_Drop”, “Lip_Tighten” – keep the naming consistent so anyone can hop in and tweak. Then, weight paint the jaw bone with a softer falloff at the angles; the corners should be heavier so the mouth stays in a relaxed shape until the lip curves kick in. For the bittersweet feel, add a little “Lip_Soften” control that nudges the corners up subtly, and bake that into the animation curves so the tension feels like a warm bite. Keep an eye on the pivot—if it’s off, your whole mouth will drift into a cartoonish grin. Coffee, on the side, helps keep the eyes from blinking too fast during those long rigs. Happy baking!