Politeness has and always will be favoured by all employers. We can be confident, assertive and polite at the same time believe it or not. This I totally agree with, but hearing this No.1 mistake that interviewers make, just made politeness even more important. 

So according to the executive managing editor of Insider Inc. she never takes a candidate to the next stage if they don't send a 'Thank you' email. 

It makes complete sense when she outlines what this act represents, but I can't say I've ever thought about it for any of my five jobs. 

Does this make me a bad candidate? Not necessarily. But it could have given me an edge. 

Perhaps it's something you should consider after attending an interview?