I discussed a project in healthcare that involved frequent pattern analysis, feature engineering and machine learning. Early on I understood that the interviewer was struggling with English, so I spoke very slowly - this did not make things better. Interviewer did not know frequent pattern analysis and got extremely annoyed that he couldn't understand the 'slightly complex' design of the project. I explained it slowly and clearly to him because I was excited about the interview at this point. The excitement was short lived.