"Don't tell girls how intelligent they are".
Because then the very analogical argument will be used to say - telling girls they are intelligent is making them under perform in other areas.
In short, if you are not ready work hard and do something on yourself by your work alone. There are plenty of reasons you can use to justify what you are.
See e.g. http://www.scientificamerican.com/article.cfm?id=the-secret-...
The key here is to take what is good and beneficial out of a talk and just move on.
Else each social persuasion and thought can ruin your life everytime one hears some one speaking.
The mindset stuff is a scientific result, it's not "after" anything.
Maybe you think you are so strong-willed and independent that you are immune to this effect, but however dumb you feel it is, the majority of people (and kids especially) apparently are not.