(and Slippery Faces): Slippery places is a reference to actual places or emotional states in which we are more likely to slip.
These are, of course, to be avoided if reasonably possible.
Slippery faces refer to old drinking buddies; the company of whom we should avoid as well.
Another similar term is 'old playgrounds and old playmates.'
It is dangerous even foolish to put ourselves in situations where we are likely to be tempted by alcohol.
Even if we believe we are now strong enough to resist temptation, we best resist temptation by avoiding temptation altogether.