The first - the pleasure principle - was that it should give enjoyment. The second - the reality principle - was that it should be an aid to present perception and mature reflection.
Good youth work also proceeds with these twin principles in mind. Since their engagement is voluntary, young people have to find pleasure and enjoyment in youth work activity. But the youth worker as an educator also wants to encourage a greater understanding of the real world around them, of social issues, and to prompt consideration of courses of action and their possible consequences.
This can be a hard balance to strike and needs to be managed well. If it is not, it can have two results. The first is that "enjoyment" tips over into being merely low-intensity recreational activity or desultory discussions around the pool table which do not really address urgent personal issues.
At the other extreme, "reality" can come across as rather heavy political correctness or a form of pre-packaged curriculum which smacks of the classroom.
Here again youth work can learn from the great poets.
TS Elliot saw three stages of development that a reader of poetry might go through. The first - experiencing enjoyment - could be followed by some attempt at classifying and comparing. This second phase - appreciation - could be followed by reorganisation of the field when the reader met something new in his or her experience.
These twin principles and three stages seem to me to be pretty close to the design of good experiential youth work, which looks to seize opportunities on the wing as well as planning for them to occur.
Maybe, while we're at it, is there any scope for introducing more young people to the pleasure of poetry in youth work, with the paths it offers between heart and mind?