In a gang of violent ruffians, "be less violent!" is great advice. A gang of extremist pacifists being beaten up by outsiders probably needs "be more violent!" as advice.
Your case particularly hits a nerve with me because "do not care what other people think!" is good advice to someone who makes decisions based on where they think the crowd is going (which is the normal way) but may as well be the kiss of death to the typical engineering mind. Engineers do not need any advice that encourages them towards independent thinking. They already have lots of training in making decisions based on objective or internalised criteria. Engineering types usually need advice on how to read body language and make decisions using social techniques.
When dealing with smart, numerate people it is better to discuss scenarios or statistical frequency of mistakes rather than "give advice". Generic advice is often useless without context.
I wish I'd had some training on how to care what other people think when I was in my teens. Would have done me the power of good.