[swombat]

I guess some people might manage to bullshit themselves into thinking the product is awesome when it's not... then again, even in those cases, there is presumably some element of the product that is awesome, otherwise they couldn't believe such a thing?

Self-delusion is a powerful force, but smart people need more than that to achieve any kind of lasting result.

[jiggy2011]

From what I understand they often start with some sort of brainwashing, they are also taught weird beliefs like "every time a customer says no the odds of the next customer saying yes will increase".

I guess it will depend on what the product being sold is, enterprise software is probably somewhat different to timeshares or double glazing.

It is worth bearing in mind though that some of the best salesmen throughout history have probably been people who were knowingly selling scams.