I worked for a number of years in a custom software dev shop and one of my later responsibilities was to be the tech guy during the sales cycle. Essentially my job was to look and sound smart and help convince the potential customer that we're really good and the best choice for the job. I do think we were pretty good but as you can imagine most of my job was bullshitting.

I can't remember the numbers of times that I would quickly read up on a topic / language / technology the prospect was using the night / morning before the meeting, then during the meeting try to sound like an expert in the topic. I know exactly how convincing I was, but I was never called out enough during the meeting to out me.