I'll second Leed on both points. My 'work experience' while short in duration, held a similar circumstance wherein I had to train others. I too have experienced the uninspired work ethic some people show.

It is only time and experience that teach us better values. They may goof off now only to be regretful at a later stage. You've made your opinion known. It is up to them to decide whether or not to take said advice.

You can rest assured that you've tried to do your best by them. Concentrate on yourself and how to improve further. That's all you can do.

As to turning off emotions, I'll leave you with this warning 'Be careful what you wish for... it may come true'
Turning off emotion comes with its own ups and downs, difficulties and can be devastating in its own way.

I wish you well and hope for a few good bounces to come your way.