Most people trying to sell crap about social engineering is BS - there are a lot of free resources out there about it - one of the less known areas of social engineering is biases. I personally use conformation bias on people at work all the time by prefixing a task with "It will be easy" and "It will only take a few minutes" even if that is a straight out lie, if they don't already have preconcieved notions about this task, they will usually stick with what I told them.