Mood-O-Meter
Mood-o-meter should be a thing that exists. How else are people supposed to know how anyone is feeling?! Oh yeah, you can read their facial expressions and gestures, but that's just too complicated and unreliable. Take a look at this:
First, she was late, then she slammed the door, and then!!! She dared eat in his clean, precious car! To top it off, she guided him 20km in the wrong direction. This is not going to end well. He is about to lose his mind when he learns this…