sometimes we can't help ourselves from saying things that are just down right mean and negative. on the guise that we want people to be realistic and not be over confident unnecessarily. noble intentions these are not. really. it isn't.
some may not guess this but the minds of the young are fairly malleable. yes harsh words may spur them, may challenge them to be better but on the flipside it may scar and affect them negatively.
in instances where you can build them up, inspire them with positivity, within reason that is, please try to choose that option. they will have more time for negativity later.