I thought it was because of how they get differential treatment because they are ugly old men. He just stares at them and says nothing but he shows a (mandatory) friendly smile to other customers. A stark reminder that the world is not kind to a freak like him (old, freakishly tall, not conventionally attractive).
Urusei Yatsura: Beautiful Dreamer is a real anime movie based on the manga Urusei Yatsura. It's a continuation of the anime series that's also based on that same manga. It's by Rumiko Takahashi, the same mangaka responsible for Ranma ½ and Inuyasha.