Have You Ever Felt Really Embarrassed?

On once occasion, I was attending a meeting with foreign customers. The meeting subject was involving with technical issues. Many specialized vocabulary were spoken during the meeting; unfortunately, I knew much less than should be. A number of questions were submitted by my customers, I lost my sense of hearing at the moment. I apologized for not in the situation repeatedly, and I felt extremely embarrassed at the same time. It was such an unaffordable embarrassment I have had.