I found working with young people really enjoyable as they are so straightforward and mostly honest with their opinions and views. They get straight to the point and rarely beat around the bush if you know what I mean.
The ones I worked with were between 16 and 24 and had become homeless for a variety of reasons, some had had really traumatic childhood experiences. Having a bit of rebel about me I found I could really empathize with many of their frustrations and even anger. It seems sad to me that our younger generation is constantly being denigrated for their behavior when I believe it is our generation that has let them down by failing to provide them with some solid foundations and parameters around which to base their lives generally.
Sorry, I could go on about this endlessly, but a straightforward answer to your question would be that I found practically every area of working with them rewarding. The more difficult and defiant the character the more effort I put into doing as much as I could to bring that young person to a happier place. It was not always easy and they did not always like what I said but because I always gave it to them straight up, they recognized that I was not trying to manipulate or lecture them, so despite some bumps along the way, my relationships with them were always amicable in the long term. I do miss working with young people but I am enjoying my writing and working for myself.