Scientists in Berkeley made an experiment in which they taped people talking about embarrassing moments in their lives. Other people watched the videos and then rated the stories based on how embarrassed they are. Then, they asked them to rate how nice the people telling the stories were.
The people who told embarrassing stories, and seemed flustered recalling them were rated as nicer as the people who told the stories, but maintained a straight face. Those people were rated as selfish and untrustworthy! The reason behind this phenomenon might be that we instinctively think that people who get embarrassed easily will go out of their way to make sure others don't get embarrassed.