2 Things Every Programmer Should Know

Are my contributions to the forthcoming book 97 Things Every Programmer Should Know by O'Reilly. I hope they're accepted. I've been thinking about practice a lot recently. The Average/Mean Time To/Since Green Game has a large element of practice designed into it. In his excellent book The Fifth Discipline, Peter Senge writes:

The total absence of meaningful practice or rehearsal is probably the predominant factor that keeps most management teams from being effective learning units.