I've been trying to think of a word recently that would be used to describe the feeling of frustration or disappointment and annoyance or disgust at others directed especially towards their stupidity or incompetence, from the person's perspective, when the person was expecting more/for them to act differently or had high hopes in general. I'm trying to avoid the view of labeling the person as being overly arrogant thinking this way.
For instance, "What where they thinking?" the Hillary supporter exclaimed, filled with (insert word here)
Indignant with his loss, the footballer sat in the changing room. Looking around, "I'm the only decent player on my team", he thought (insert word here)ly.