self fulfilling prophecies and labelling

do these things actually occur? after u think or say something about yourself......will it really happen? and what if you label someone "smart" or "kind" or "good"..........will they live up to it?

Definition by Wikipedia:

The self-fulfilling prophecy is, in the beginning, a false definition of the situation evoking a new behaviour which makes the original false conception come 'true'. This specious validity of the self-fulfilling prophecy perpetuates a reign of error.

So needless to say, wiki still defines it as false......to start with......
Ahhh.....the weight of thoughts.....and labels (labelling a person)

I remember in Sec 1, i was feeling flu-ish and my friend told me "Don't keep saying and confessing that you're sick, if not you'll remain sick or get worse. Instead say 'I am getting better or I am good'".